diff --git a/api/app/src/Repository/ClientRepository.php b/api/app/src/Repository/ClientRepository.php
index e9ef95487c..149f2072c9 100644
--- a/api/app/src/Repository/ClientRepository.php
+++ b/api/app/src/Repository/ClientRepository.php
@@ -135,20 +135,20 @@ public function findByCaseNumber(string $caseNumber): ?Client
             ->getOneOrNullResult();
     }
 
-    public function findByCaseNumberIncludingDischarged(string $caseNumber): ?Client
+    public function findByCaseNumberIncludingDischarged(string $caseNumber): mixed
     {
         $filter = $this->_em->getFilters()->getFilter('softdeleteable');
         $filter->disableForEntity(Client::class);
 
-        $client = $this
+        $clients = $this
             ->getEntityManager()
             ->createQuery('SELECT c FROM App\Entity\Client c WHERE LOWER(c.caseNumber) = LOWER(:caseNumber)')
             ->setParameter('caseNumber', $caseNumber)
-            ->getOneOrNullResult();
+            ->getResult();
 
         $this->_em->getFilters()->enable('softdeleteable');
 
-        return $client;
+        return $clients;
     }
 
     public function findByIdIncludingDischarged(int $id): ?Client
diff --git a/api/app/src/Repository/PreRegistrationRepository.php b/api/app/src/Repository/PreRegistrationRepository.php
index fdd14c3d40..6a8b524015 100644
--- a/api/app/src/Repository/PreRegistrationRepository.php
+++ b/api/app/src/Repository/PreRegistrationRepository.php
@@ -65,6 +65,18 @@ public function getNewClientsForExistingDeputiesArray(): array
     {
         $conn = $this->getEntityManager()->getConnection();
 
+        /** Query to retrieve the new clients to be made from the PreReg table for existing deputies.
+         *
+         * Inner query is comparing the combination of deputy uid and case number (which is akin to a court order, just without the report type)
+         * Compares the combinations that exist in PreReg (essentially Sirius) with the combinations from User & Client table (Digideps)
+         * This gives us which combinations do not exist in Digideps
+         *
+         * Outer query bring backs fields and links PreReg table to User table via deputy_uid
+         * This is so we are only focused on deputies that have signed up and have a deputy_uid.
+         *
+         * We then compare the combinations of deputy uid and case number from the outer query with
+         * the combination of deputy uid and case number from the inner query.
+         */
         $newMultiClentsQuery = <<<SQL
         SELECT
             pr.client_case_number AS "Case",
@@ -92,10 +104,16 @@ public function getNewClientsForExistingDeputiesArray(): array
             pr.client_address_5   AS "ClientAddress5",
             pr.client_postcode    AS "ClientPostcode"
         FROM pre_registration pr
-        LEFT JOIN dd_user u ON pr.deputy_uid = u.deputy_uid::varchar(30)
-        LEFT JOIN deputy_case dc ON u.id = dc.user_id
-        LEFT JOIN client c ON dc.client_id = c.id
-        WHERE c.case_number != pr.client_case_number
+        INNER JOIN dd_user u ON pr.deputy_uid = u.deputy_uid::varchar(30)
+        WHERE (pr.deputy_uid, pr.client_case_number) IN (SELECT deputy_uid, lower(client_case_number)
+                                                         FROM pre_registration
+                                                         GROUP BY deputy_uid, lower(client_case_number)
+                                                         EXCEPT
+                                                         SELECT u.deputy_uid::varchar(30), lower(c.case_number)
+                                                         FROM dd_user u
+                                                                  INNER JOIN deputy_case dc ON u.id = dc.user_id
+                                                                  INNER JOIN client c on dc.client_id = c.id
+                                                         GROUP BY u.deputy_uid, lower(c.case_number));
         SQL;
 
         $stmt = $conn->executeQuery($newMultiClentsQuery);
diff --git a/api/app/src/v2/Registration/Uploader/LayDeputyshipUploader.php b/api/app/src/v2/Registration/Uploader/LayDeputyshipUploader.php
index f84a57ef5d..ae9edb2d65 100644
--- a/api/app/src/v2/Registration/Uploader/LayDeputyshipUploader.php
+++ b/api/app/src/v2/Registration/Uploader/LayDeputyshipUploader.php
@@ -141,21 +141,33 @@ private function handleNewUser(LayDeputyshipDto $dto): ?User
 
     private function handleNewClient(LayDeputyshipDto $dto, User $newUser): ?Client
     {
-        $existingClient = $this->em->getRepository(Client::class)->findByCaseNumberIncludingDischarged($dto->getCaseNumber());
-
-        if ($existingClient instanceof Client) {
-            foreach ($existingClient->getUsers() as $user) {
-                if ($user->getDeputyUid() == $newUser->getDeputyUid()) {
-                    throw new \RuntimeException(sprintf('a client with case number %s already exists that is associated with a user with deputy UID %s', $existingClient->getCaseNumber(), $newUser->getDeputyUid()));
+        $existingClients = $this->em->getRepository(Client::class)->findByCaseNumberIncludingDischarged($dto->getCaseNumber());
+
+        if (count($existingClients) > 0) {
+            /* @var Client $existingClient */
+            // If there is an existing active client, we shouldn't create a new instance of the client
+            foreach ($existingClients as $existingClient) {
+                if (!$existingClient->isDeleted()) {
+                    throw new \RuntimeException(sprintf('an active client with case number %s already exists', $existingClient->getCaseNumber()));
+                }
+            }
+            // Loop through the discharged clients to ensure we are not creating an account for a deputy associated with a discharged client
+            foreach ($existingClients as $existingClient) {
+                foreach ($existingClient->getUsers() as $user) {
+                    if ($user->getDeputyUid() == $newUser->getDeputyUid()) {
+                        throw new \RuntimeException(sprintf('a discharged client with case number %s already exists that is associated with a user with deputy UID %s', $existingClient->getCaseNumber(), $newUser->getDeputyUid()));
+                    }
                 }
             }
-        } else {
-            $newClient = $this->clientAssembler->assembleFromLayDeputyshipDto($dto);
-            $newClient->addUser($newUser);
-            $this->em->persist($newClient);
-            $this->added['clients'][] = $dto->getCaseNumber();
         }
 
+        // Only create a new instance of the client if one doesn't already exist,
+        // Or if all the clients are discharged, and we are creating an account for a deputy that is not associated with this case number already
+        $newClient = $this->clientAssembler->assembleFromLayDeputyshipDto($dto);
+        $newClient->addUser($newUser);
+        $this->em->persist($newClient);
+        $this->added['clients'][] = $dto->getCaseNumber();
+
         return $newClient;
     }