Might be worth having two new clevis pins to hand and all the gaskets (one under each m/cyl and one under the plate). If not done already then do steady bushes whilst in bits.
Make sure you get the correct plate too - there are various ones with different size holes, some of the later ones have the brake master cyl hole offset and hence won't fit. M-machine stock most of them if nowhere else does.
By rights you should have the taller 'S' brake master cyl if you are replacing them 
so I need the full twin type gasket for under the plate then?
yep plan to paint & replace the bushes
minispares looks like they stock all these parts, not checked the pins though.
yep I plan to buy the original tin cylinders (bloody expensive though)!
Anyway the most I have done on my mini is replacing all the cooling system, how hard & how long would it take? I'm going to get a quote from a MG specialist I use.
I totaly agree a repainted block would really do the trick...I will tackel it one day! lol
Thanks
Craig.