My oh my this is a strange forum...you boys obviously have a great time winding each other up!
Marcus, hadn't thought about timing, but that seems like the obvious next place to check considering the symptoms. Man, I don't even have a timing light in this country (I'm a Yank, apologies) - will have to do the trial and error method.
Quick question about those freewheel hubs. You said you had to engage them to lubricate the bearings every now and then, but I was under the impression that occasionally engaging the 4 wheel drive (with hubs in freewheeling mode) would achieve the same thing - is that right?
Right, off to get grimey...will report back...over and out.