Started a separate thread on this but will post here as well.Well started to strip the gearbox on the A7(haven't really touched it in years) and took off the outer cover. Inside it was obvious something was wrong. The circlip holding the mainshaft small ball bearing was half out because half the alloy housing has broken away and was wedged behind the kickstart ratchet. This could explain why the kickstart sometimes jammed, I found a bir more housing lying in the bottom of the outer casing.
Who knows what could have happened if those bits had got into the main case