A couple of things -
1. how do the lifters actually work, and why do they make that tapping noise? Is it because the internal spring is broken?
2. can they be accessed without removing the cams, or indeed can the cams be easily removed and refitted, without doing the belt etc? Belt change not due for another 10k, but cam cover gaskets need done now.
3. I'm hoping to do this myself when changing the gaskets and cleaning the breathers, but wanted some guidance and advice in case I should leave it to a proper mechanic! Particularly if the cambelt has to be done at the same time, though I have the DVD and might just give it a go as well :-?
4. I have seen Marks DTM guide to cleaning the lifters once they are out, but will try and source some new or good condition used ones (a couple anyway) prior to starting - just in case some may need replacing.
Sorry for the potentially stupid questions, and I guess there could be more to follow

Cheers in advance