There was a disabled lad in a wheelchair that couldn’t walk and at the end of the series it turned out he’d been pretending all the time and he could actually walk. There was a really tense but where he was watching someone and he tried to kill them. I think it was revenge for his Dad who had been killed or something?
I thought it was a series of Unforgotten but have googled and it isn’t. DH thighs might be a foreign police drama but I thought the guy was English.