This is a follow up to a thread I started some time ago under 'blind panic'. Bascially, the main timing chain was loose and took out the bolt that holds the timing chain guide in place. You dont want that rattling around! A couple of points I thought may be useful to anyone else thinking of doing the same:

1. You can do this without dropping the sump or taking off the head
2. The main chain may not come off without removing the tensioner arm
3. The arm pokes up through the head so you need to remove the pivot at the bottom to get it clear. The diagrams you will find at real.oem etc are wrong-it isnt a bolt but a dowel.
4. There are dirty great timing marks on the flats of the camshafts so dont panic if you are not sure where the lobes are supposed to be
5. If you get hold of the special tool to lock the crank and cam read the manufacturers notes. They may say the crank lock wont fit because of rust in the hole and to get the cam lock to fit you need to snuggly you need to put some feeler guages between the tool and the cams :-)

I replaced both chains, both guides and the tensioner arm and spring. They were all shot. Total costs incl gaskets was about £140 inc VAT.