Yeah I agree no problems with Halfords exchange policy at all. Used it many times myself and straight swap much easy than snap on.
I bought an old Snap-On 3/8 ratchet many years ago that has sat in the bottom of my tool box mostly unused due to the teeth being buggered and it undoes until you get to the bit with no teeth and it annoys me. I was talking to my cousin(a mechanic) about it being the only Snap-On tool i owned. He said to bring it in and he'd have a word with his rep. I got a text a few days later saying he showed it to Ian(Rep) and he only carries one service kit for those in his van and unfortunately used it but he'd repair it the following week.
When it was fixed i went to collect it and my cousin asked me how old i thought it was? I guessed 1970s. He said no. MUCH older. He said it was part of the standard tool kit in the WW2 Sherman Tank!
Ian repaired it for free too!
I can't comment on Halford's tools, but i wouldn't take a car of mine for an MOT.
I took mine in for a discount price. It failed on one headlight out of alignment, a trackrod end and they couldn't lock the rear seat upright, it was an estate car.
I'd just replaced the one trackrod end as that was what the seller told me needing fixing for the MOT. After waiting for the promised telephone call from Halfords regarding the result, and not getting one, i called them again. He told me what it failed on. I asked for a quote. Stupidly asked...
It was about eight years ago but i remember it was just under £300 to do the headlight and trackrod and they suggested welding the back seat back in the upright position! WTF???
They wanted about £50 for the headlight adjustment and a full four wheel tracking!
I went to collect it. Got the headlight done for nothing at a garage that then got my MOT business for the next few years until the two guys that MOTed my cars left and set up on their own and now they have it. The trackrod took me another twenty minutes and £8 from Euro and i discovered that the plastic piece inside the seat back had moved because the two screws that held it in place had come out. About five minutes poking with a screwdriver moved it back near the hole so let me get first one screw and then another into it and it too was back in the car and locked upright.
My mechanic has had a few cars come in for welsing work that Halfords has said needs doing and they couldn't see it and sent it around the corner where it either passed, or just passed on the non existing rust and failed on something else.