It’s wrong of them to tell you you can’t have another termination for a faulty car, especialy one that ‘s a safety hazzard. Typically you are allowed three termination and can charge a termination up to £250, which shouldn’t apply in your case.
If the safety issues have been fixed, but keep comming back, as you say – I would phone again (hopefully another person answers) and put weight on the drivers seat that eeps coming loose, in that its dangerous should it come loose whils’t driving and heave forbid involved in an accident. You could apply equal weight to the buzzing noise whilst turning and your worry something might happen.
The dash waping is cosmetic and, s long as it doesn’t hinder your view of the road, I’d apply less weight to it, but still worth mentioning.
If they don’t budge put a complaint in and go from there.