Oh im sure they would have charged you over £100 anyway. Usually they start at one end and replace an item at a time with new until they fix it, fine if they get the faulty part 1st but not so fine if they dont. Once they fit a part then its yours, even if it doesmt fix it and proves that your part was ok, they still charge you for it. Most of the repair was labour on your scoot so i expect the bill would run to at least 2-4hrs labour, most charge at least £40-£60/hr just for labour so even going on the lowest time and price it would be near £100 plus parts.
See if you can find a good local independent small bike repair shop for the future if you ever need it, i have a good guy locally who often tells you how to fix it yourself, he tells ypu exactly what he would do 1st so you can go home and check yourself for free, hes a decent guy, one of the few mechanics i trust.
