The message
from Appin contains these words:

Sadly it doesn't answer the problem of those in the Northern half of the
UK where, even on the mainland, there is NO free delivery from
Screwfix, no matter what the order. Hence Screwfix is on a list of
non-preferred suppliers.

Not what it says on the website. You just don't get next day delivery.

"Premium delivery options not available for other zones".

Other zones appear to be Scilly Isles, Isle of Man, NI and Highlands and
Islands of Scotland. The latter being the Northern half of the UK only
on a matter of length, a significant amount of which is open sea. In
terms of area not more than the Northernmost quarter.

--
Roger Chapman