It's ok kwick fit say it doesn't need done so must be true
I got as far as the first line where it mentioned kwik fit. That would be enough for any sane person to walk (or run) past this one as quickly as possible. I wouldn't trust kwik fit to put a tyre on the right way round, never mind letting them have a full car to bugger about with.
As for the cambelt. No point getting into any arguments or discussions with sellers about it. Just allow yourself the time and money to have it done yourself when you've bought the car. If a dealer is prepared to have it done to clinch a sale then rest assured it'll get a new belt at most, and no rollers or tensioner. And he'll correctly say that the belt has been replaced. However, there'll be no warranty on the belt replacement job, just the usual dealer comeback on the car as a whole. If you have the belt changed yourself at a main dealer (for example) then
YOU get 2 years warranty on the job, and the assurance that comes with it.
Also, private sellers won't be having the belt done to clinch a sale, so not even worth raising the matter with them.