We have two shipping methods for customers:
Free UK delivery
Free Local Delivery (based on specific postcodes)
Problem: customers eligible for local delivery keep choosing Free Delivery and so they get processed along with national orders in error or they wait longer when we could have their orders out and delivered in a day.
Question: is there a way of disabling all other shipping methods if a customer is eligible for the local delivery shipping method?
Unfortunately, this is not possible directly with Shopify since it requires differentiation based on postal codes. However, our Multi Carrier Shipping Label app can be of help here. To handle this, you can create a shipping zone with all the required postal codes for which you offer "Free Local delivery". You can now create a rule for shipping rates such that when customers from this zone comes at checkout, Free Local delivery is shown and for all others, Free UK Delivery is applied.
For any help required, you can contact our support or directly give a call at 1-831-267-6349.