Sorry Rossco66 - I hadn't spotted your response...
Anyway, I managed to score another fluid reservoir which stopped the leak.
I also scored another set of calipers, master, cable and lever from what must be a later model Z1R.
There are 2 differences - firstly the pistons are 42mm rather than 38mm (a 22% increase in piston area by my maths) and secondly the master cyclinder actuating lever is different - the later one has an offest pivot point (the earlier one being in the centre).
I've yet to test properly but it early signs are that these brakes are a huge improvement over the earlier ones!
Picture showing join where reservoir was leaking from:
http://i12.photobucket.com/albums/a233/ ... bny1cc.jpgPicture showing different master cylinder levers:
http://i12.photobucket.com/albums/a233/ ... u3drkk.jpg