diff --git a/.github/workflows/_deploy_lambda.yml b/.github/workflows/_deploy_lambda.yml
index 420f9504..3cef705e 100644
--- a/.github/workflows/_deploy_lambda.yml
+++ b/.github/workflows/_deploy_lambda.yml
@@ -121,15 +121,21 @@ jobs:
           TF_VAR_google_solar_api_key: ${{ secrets.TF_VAR_google_solar_api_key }}
           TF_VAR_ordnance_survey_api_key: ${{ secrets.TF_VAR_ordnance_survey_api_key}}
         run: |
-          EXTRA_VARS=""
+          ECR_REPO_URL_VAR=""
           if [[ -n "${{ inputs.ecr_repo }}" ]]; then
-            EXTRA_VARS="-var=ecr_repo_url=${{ steps.repo.outputs.ecr_repo_url }} -var=image_digest=${{ inputs.image_digest }}"
+            ECR_REPO_URL_VAR="-var=ecr_repo_url=${{ steps.repo.outputs.ecr_repo_url }}"
+          fi
+
+          IMAGE_DIGEST_VAR=""
+          if [[ -n "${{ inputs.ecr_repo }}" ]]; then
+            IMAGE_DIGEST_VAR="-var=image_digest=${{ inputs.image_digest }}"
           fi
 
           terraform plan \
             -var="stage=${{ inputs.stage }}" \
             -var="lambda_name=${{ inputs.lambda_name }}" \
-            $EXTRA_VARS \
+            $ECR_REPO_URL_VAR \
+            $IMAGE_DIGEST_VAR \
             -out=lambdaplan
 
       - name: Terraform Apply