If you have gone through insurance as you suggest it will go down as a non fault accident. I have previously watched these small dent companies that come to your home, paint several area’s of a neighbours deceased fathers picanto, where they didn’t even bother to tint the paint to make it suit the aged standard red of the car. Needless to say it looked idiotic.
I wasn’t given a choice about where the car was repaired but if I had been then I probably would have chosen the mobile option anyway, as I have modifications to my vehicle and trying to get a suitable hire vehicle whilst mine was away would have been difficult. I just assumed that you would get the same quality of repair wherever the vehicle was.
There is no reason you can’t get just as good repair from these types of companies. However it appears the technician that came to fix you was too lazy to remove the bumper and too lazy to use a bit of filler at the bare minimum, so he could complete the job to a high standard. Getting the company back out to complete the work to the required standard is the least they can do.
It seems he was either running behind that day or after an early finish!
Its unlikely the shoddy workmanship will effect you getting the good condition bonus/payment at end of your lease. What you d next depends on whether you can live with the repair or not. At the very least you should do is rate them negatively on the questionaire they sent you.