Ouch Patrick, still battling? From your description, your main problem sounds like the zone definitions rather than the shipping implementation. These 'I want all of it except that bit and that bit' definitions are always tricky.
If you visit www.mutualadvantage.co.uk, Kevin has a UK template which has a pretty good Country, County Zone setup for the UK, which should solve your problem, as the country is divided up into England, Wales, Scotland, Channel Islands, etc etc.

Rgds,

Chuck