Forced to ship certain orders with Evri

We only have Amazon Shipping switched on for all our shipping templates, only have Amazon Shipping selected as preferred carrier in shipping settings yet everyday we have a handful of orders which only allow us to ship using Evri. We do not spend enough with Evri to have collections, so have to make a 1-hour round trip daily to the Evri depot to drop the parcels off.

When setting up shipping templates, all non-mainland areas are unticked yet these orders just seem to creep through. Has anybody found a way around not being forced to use Evri to ship to certain postcodes?

Thanks.