Cheers for the replies, I called Craddocks and they told me it will be the 591231, have ordered the 591231G which should be the OE one and a master cylinder as well
Already had the old cyl off at the weekend, found it was not too bad once I removed the exhaust down pipe first
Have used those pressure bleeders before, very useful especially if you have no one to pump the pedal for you ... of course I've not used it in years so will have to turn the shed upside down to find it probably