Shockingly bad technical and customer service received from Tesla Dartford (notwithstanding a friendly staff) Sent my car for an MCU+Tuner upgrade, intermittent GPS and internet connectivity failure. This took them more than 4 working days and cost me £2450 :'( I had also asked for Noise, Vibration and Harshness (NVH) assessment done which would have cost me additionally. Enquired at the time of leaving the car with them if anything inside (car seats, stuff etc) needs to be removed, was told it wasn't necessary. However, on getting back the car was informed NVH wasn't done because there was stuff inside the car, doh! Brought the car home, the internet issue was fixed but GPS never worked at all. It's been 3 weeks since and it still shows the car location at the service centre :( The Sentry mode was supposed to start recording videos as a result of the MCU upgrade, but never worked. Displays 'saving video' message but when checking out the videos shows no videos found, what a dud! I wasn't offered a courtesy car even though my car is under extended warranty (£3.4K from Tesla). Apparently only the original warranty covers courtesy car, nice! On top of that, each time I talk to the service guys I have to remind them that the car is under extended warranty as their system has no clue about it despite purchasing the Helvetica warranty through the Tesla site!!   Now I have to take the car back in for them to fix the GPS and Sentry Dashcam issue which happened as a result of them doing a half-arsed job in the first place and lo and behold I wouldn't get a courtesy car. Why? Because according to Tesla I don't even have a warranty, forget about paying £3.4K for the extended warranty through the Tesla site. It's all the customers' fault- we purchased their cars without reading their service reviews on here!!! By a disgruntled Tesla Model X owner (028128)