Well I got the job done today, my friends at Autostore in Cambridge showed me how they could remove the ignition barrel and steering lock in about half an hour !! Take off two panels under steering wheel ( just a couple of screws), reach up inside instrument panel and release speedometer, remove speedometer from dash panel. Reach inside speedometer hole and undo screws holding steering column in place to allow steering wheel to fall about 1-2 inches. reach behind ignition switch and undo three small screws ( very fiddly) that hold ignition switch to lock mechanism. It is now possible to wiggle the steering lock/ignition barrel free and remove from car. They then drilled out pins, inserted new barrel and secured with new pins. Then reattach ignition switch to lock mechanism, wiggle it back in place, replace speedo and panels, Job done. Pavel at Autostore took about 20 mins mat most to re assemble but then he has a very good knowledge of the dashboard construction of these cars haveing done similar jobs on one before. When he had finished it was sticking in one position and then jamming so he took it out, greased it thoroughly and then re assembled as above and its now working perfectly, and I hope will continue to do so.
So if you really really know what you are doing, you could do the job in under two hours, but I would honestly say for a complete beginner, at least a day !
Good luck if your going to try it
Howard