Best bet is to push them continuously until you get a decent answer - it's a pain but it seems to be the only thing that will get them to take any action - wont work if you don't have any warranty to fall back on though.
Just to update this - I have pushed them by writing letters now and again when I've had nothing to do.
SEAT UK generally respond by calling me, although they have the uncanny knack of calling when I'm in the middle of something and it's hard to instantly recall all the details and have a sensible discussion.
Anyway, the suspension bush failure they just regard as hard luck despite the low mileage. I pointed out that Skoda will pay for it and they said nothing to do with SEAT. The drum brake servicing they said is down to the dealer - I couldn't get the customer service girl to agree that the SEAT service schedule is inadequate and if something needs servicing in order to get it through the MOT then it should be in the service schedule. Cars are supposed to pass the MOT - it's absurd that the dealer should do a major service then MOT the car only for it to fail.
They offered £100 and then £200 in goodwill vouchers - however I can't really use that as the next service is on a dealer contract and I certainly won't be going back there once that's expired. The dealer may create other work though.
Due to the dealer messing up the MOT renewal date I've already had this year's MOT done in our village garage and the car passed.
I'm convinced all this hassle is caused by the dealer scamming me when there was actually nothing wrong and it's that that I feel most annoyed about. The car needs changing now and I don't think I could bring myself to consider an
Ibiza and it's put me off VAG as a whole.