Thanks for all the helpful comments :-)
I'm going to keep my eye on eBay then for the P4 calipers (not worried about fashion I still have some flared jeans!) and also for a master cylinder. If no calipers turn up before my pads wear out i'll try some of those suggested here. When they do turn up i'll also use those suggested here with them.
Regarding the sag, its not set up correctly yet as i'm going to fit an Ohlins shock that i have quite soon, but will do it after that.
Cheers
Simon