The thing is though Bosch have quoted you £99 I presume without seeing what’s required and they may honour that if it gets a bit more complicated, the lad who’s sent out may be a self employed contractor who works constantly for them and can take a hit on the odd repair as a ‘swings & roundabouts’ situation. The scenario you want is a one man band taking the job on for say £75, which after his overheads (van, tools, insurances, lack of benefits etc) would mean it may come down to the fifty quid mark say. The latter operative’s nightmare is that the job escalates, as they very often do, and he has to approach you for more money, situations like this on occasions become a bit messy. £99 for Bosch to do it is a small price to pay just for their bill headed paperwork alone.