Ok well in a turn of events I've just bought a ULF/TCU loom. I'm going the full factory route .. call me mad but it was an absolute steal on eBay. I have fitting instructions too.. it's actually not as bad looking as it sounds. Over the next few weeks I'll pick up a BT antenna, mic and a ULF/MULF should work out a lot cheaper than the dension option.
It'll be a good excuse to try out my new ISTA-P install..