Right, an update for anyone that's interested.
So I thought about using a PICaxe for a while, and forgot about the project for a bit. I've almost finished the 9V supply, and I'm about halfway to upgrading my adder to an adder/subtractor.
I bought a PIC book (The PIC microcontroller, Your Personal Introductory Course) which is Ok, it convinced me that Hank was right, so I've skipped over PIcaxe etc. I've bought a PICkit 2 (with demo board, which looks useless!) and a few PICs, hopefully I'll start experimenting soon (once the crystals arrive, which I forgot to order!) and the code should be fairly simple I hope!