As the others have said already I'd doubt Halfords wouldn't swap it.
In a similar situation I bought a gerber multi tool about 15 years ago, I broke the blade on it last year being a bit of a bell and using it to try and lever something. I had no receipt but fired them an email. They sent me a new one out no issues.
In general, depends on the staff, but I've been told before that the moving parts aren't covered,but they do a repair kit.
Just, er, don't assume that the repair kit is free and walk out of the shop with it, else you might get chased across the car park by a slightly cross employee. Hypothetically. Ahem.
The moving parts weren't included but they changed it so now they are. Their excellent guarantee helped me make a decision to buy a tool chest and fill it with their tools when I decided it was time to treat myself last year.
Following on from what others have said, a friend used to work for them, and they changed their terms&conditions a few years back and got told to replace items with no quibbles...
This is true but it was my understanding that ratchets were still not covered for the mechanisms, which is why they still stock repair kits for them. The reason the "no quibble" instruction came in was due to a receipt issue after they changed to thermal printers, where the receipt would actually go blank after as little as 3 months, or black out if exposed to constant heat (even having it in a trouser pocket for a couple of days was enough to make it go black).
In saying that, recently the repair kits became obsolete and were sold off. So maybe it's all change. Would be interesting to know for sure.