its easy to do, but time consuming, like i said, very boring. lots of nuts and bolts to fiddle with, and everything has to be done in sequence otherwise you snap things that should not be snapped.
i was gonan get it done, but then i bought the tappets, got bored one saturday morning, and did it my self, all you need is spanners and a socket set.
timing is tricky, i marked mine up on the belt and wheel, made sure it all lined up when i put it back together, and while doing it made sure the belt didnt jump a tooth by tieing it up tight to the bonnet(improvised with strin!) and just took my time.
looks a big job, but trust me its not at all. easier than mucking about with stereo installs and stuff.
just make sure you buy a decent gasket for the rocker and you get all the old gasket off too!