Thanks for this, bear with me here are you saying I can do the cam belt myself? because I know its an expensive job, I suppose that also makes sense about the service as even though I do it now when I try to sell people will always be suspicious about the previous absence of SH.
Where do I start with cambelt etc?
The cambelt is do-able as a DIY job, but it is a big job and not for the novice I would say. What I meant was, if you just at the moment want to do oil/filters/plugs, then do them yourself and save a packet. If you want to tackle the cambelt, you will save a lot of money, although I'm not best placed to advise the procedure as I don't own an IS.
As far as inspecting the cambelt goes, that is a doddle, and just involves removing the top cover right at the front end of the engine. There are a couple of bolts, one either side of the cover i believe, undo them and the cover lifts off. You will see the cam pulleys with with belt running over the top of them. If it looks in good condition, then the urgency to replace it could be reduced. On some IS's on here, the cambelt was actually worn/shredded to half its normal width. If it was like that, then you would want to get a bit of a wriggle on to renew it.