Ok then guys a quick update. Problem turned out to be the fuel filter assembly having a buggered diaphragm on the inside and the priming handle/lever being farked. Also noticed on of the feed pipes to the filter was slightly torn and the combined above causing air to be sucked in and ny girl not starting.
So quick googlefu showed someone braking an xj 5 miles away, and 30 notes later swapped out the whole assembly and changed the length of pipe for a good one, cranked engine a little followed by priming the filter and every 30 secs undoing the bleed screw a little to release air and after priming for maybe 3 mins as the resistance grew, screwed her back down, keys in and vroom vroom.
Smiles all round