Distance across UK is irrelevant to charge for delivery with the Royal Mail. It's only the size and weight that count.
That's true for 'Standard Parcels' (3 to 5 days). For other ParcelForce services (such as 9am, 10am, 12am, ParcelForce 24 and ParcelForce 48) the UK is split into 3 zones:

Zone 1: Most of mainland UK
Zone 2: Highlands and Islands of Scotland
Zone 3: Northern Ireland, Isle of Man and Isles of Scilly

(the Channel Islands are in Zone 4, and the Republic of Ireland in Zone 5, then the rest of the world in subsequent zones)

It might be rare to receive an order from a customer in Zone 2 or Zone 3 who wanted next day or 48 hour delivery, but if you did, you wouldn't want to pay the extra zone rate for the carriage yourself

What problems are you having installing? Your screenshot is a bit too small to read, but it looks like either your language files aren't being found or you haven't run the SQL.