@Big G That'll most likely be my next option if this seal kit doesn't work. Not sure who you used but I seen on a couple of threads people using a company up in Qld called "Master Cylinder Exchange". Being down in Vic I'm sure I could find someone locally.
@altezzaclub I started to pull apart the master cylinder and had the same problem, unscrewed that hex nut and the seal block did not budge. Tried to give it a knock as per the service manual, I might have been a bit to careful, but wouldn't move. Seal kit arrived this afternoon so I'll give it another go over the weekend. If it doesn't budge I'll follow on with the rest of the instructions and see how I go.
Again, thanks heaps for the information, it's been fun getting stuck into it.