Thanks to all for advice, after 4 hours, 3 homemade pullers much use of the oxy bottles and air chisel 6 holes drilled through the gear a litre of wd40 blood, sweat, tears and swear words that had not been invented (I ran out of the usuals after the first ten mins) it finally let go. needless to say a new gear was required. Anyway that's that done so its ready for its trip to allysport to have very large intercooler fitted I will keep you posted on the improved performance/ fuel economy when it happens (week tomorrow all being well).
Thanks again Icky