Thanks everyone. I cobbled together a slide hammer out of bits bought from a hardware/timber shop including an expanding wall anchor as suggested by a couple of people, £4 the lot!, interestingly, the guy in the shop suggested using an M6 anchor even though an M8 or M10 would have gone through the inner race and he was right. Some proper direct heat from a blow torch, clamping in workmate and a number of sharp downwards taps got it shifted.

On to shimming up the bevel drives and valves now.
Thanks again.