Phil B's video on taking out the engine gives a good idea of what is involved - my son and I did ours in a few hours using this as a guide - complex/fiddly (esp as we both have big hands) but not difficult if you have the space, a hoist and the range of imperial/metric tools required.
Our car had no hole at all in the bell housing for inspecting the rubbers so we did the Bleazey conversion once the rubbers had done ~10,000 miles as we do long tours and wanted to avoid the risk of failure - as it happenns, the used rubbers looked like new....
