The audi timing belt kit costs £75 + VAT and contained the belt, tensioner pulley and the small idler pulley (ie the one that is screwed onto the tensioner damper).
I changed the waterpump, plus all of the above, but not the damper. Gave it a good visual and checked it for leaks when I compressed it for re-fit.
I went for the gen audi waterpump too - plastic impeller in all.
5 hours including numerous cups of tea and breaks, in a well equiped garage with all the right tools, albeit no air tools. Not too difficult a job for a competent/experienced DIY mechanic.