Interesting you should mention this. Its caused a bit of a dilemma for me. We only have one car now and its due for MOT in three weeks. Normally we take to Darlington 17 miles away which usually involves either me following on the scooter (out of the question in this weather) and leaving it or sitting around in the garage (also out of the question now) and hoping it passes and doesnt need work, sometimes they have a courtesy car. Anyway I found a garage between Barnard Castle and Darlington yesterday (about 5 miles from here) that does drive through MOT's and I asked how it worked with the Covid restrictions and she said and I quote "You just drive up, stay in the car and we do the test with you in it". I said "well dont you need to come inside the car and she said we just get you to press the brakes etc! The only downside I can see is she said if its a fail where its dangerous to drive you wont be allowed to take it home which would be a problem but I cant see that happening.
Never heard of this kind of MOT before but maybe there is something like this in your area.