Volvo S40 knock sensor replacement

I've seen so many negative feedbacks about MOTs, delays etc. My story was a bit different and the Fixter Team - specially Alex - went above and beyond. Long story short the exhaust has to be replaced on my Smart Fortwo 451 and all the garages including Mercedes does not have any kind of exhaust not even aftermarket ones. The Mercedes got that part on back order since last year. Most of the garages refused to do the job if they are not supplied the car parts due to the warranty issue. Halfords gave me a quote for the job but it turns out they were unable to get the parts also for months. So I had enough to chase garages for 3 months. I've asked the Fixter Team to find me a garage who is able to fix the exhaust if I supply the part as I managed to find an aftermarket one made by BM Catalyst (BM 4514900081) - most of them doesn't fit due the the emission rule has changed in the year of my car produced 2009-10 - but this one does with the fitting kit (FK91590C). Anyway, Alex called me back a day later and confirmed one garage able to do that, but without collecting the car, however I wasn't really keen on the option anyway and the garage is only few miles from my flat. So he booked the garage, I brought the part, I went to the garage early morning on that day and it turned out they are actually Smart specialist - called Hares Servicing in Littlehampton - by midday the car was ready. Fixed payment went through online after the garage issued the invoice. No extra works, no extra charges etc. Absolutely recommend the Fixter and that particular Garage as well.