The adaptation issue isn’t a Motability problem. It’s either down to you ordering the wrong adaptation (if you didn’t specify that you needed the inline version), or the adaptations company fitting the wrong one (if you ordered the inline version and they fitted the standard version). That being said, you would expect the adaptations company to check that what they were fitting didn’t foul something as critical as a gear stick! I’d suggest that you call the adaptations company and explain the problem. Hopefully they will rectify it for you.
As for the issues with the car itself, that’s for the supplying dealer to resolve. You do seem to be exceptionally unlucky don’t you? My concern for you is that if these issues aren’t resolved to your satisfaction, and you request yet another early termination from Motability, I think that there’s a very good chance that they will terminate your access to the scheme. Early terminations are costly for the scheme and affect the prices that we all pay, so they have to draw the line somewhere.
Good luck and let us know how it works out.