Hey Steven
I realise that you may not mean to sound offensive, but the tone of your posts indicates that you resent the fact that some people are offering complex solutions for a small fee.
When you have been working with this software for as long as some of us have been, you get to appreciate the high degree of input (time and skill) that is often required to provide quick and easy solutions for complex challenges faced by our community of users.
Some people are philanthroipc enough to devote their time and skill to solutions which they then make freely available. Other people have used time which could perhaps have been devoted to commercial gain, and they then offer their handiwork at a price.
Rick Suffolk and I have been configuring zencarts for people for many years - people who have a serious commercial intent for their webshops - and we know when it is appropriate to suggest to our clients that they are better off stumping up a few more pounds for a solution that's already available, rather than to have us re-invent the wheel for what could be an even higher price.
As I said earlier, your shipping needs can be configured using a number of methods - those methods being based on the large array of free modules on offer. So what you want is actually there for the taking - if you are prepared to do the (relatively simple) adaptations yourself, then you won't need to spend any money at all.
Rick and I were just pointing out that Connor's mod is a wheel that's already been invented... we were not insisting that you avail yourself of it.
There are nearly a million posts on this forum, of which about two-thirds are solutions to various challenges. I have put up a large number of help posts relating to shipping and if you dig these out, you'll probably be well on your way to configuring your shipping...
BTW, there is a UK Royal Mail module in the downloads area. Why not try that one... it is (afterall) free...