My bad blood with them goes back before OCUK/Millennium was born.
A shop had opened in Manchester so my mate wanted a graphics card he'd seen in a PC Magazine. I rang up to confirm they had got one and we set out for the store only to be told they hadn't. I called for the manager but no apology was given.
2nd time a very similar thing at the same shop. I asked to speak to the Manager to confirm the item was in stock and once again it wasn't. This was around 140 miles of wasted time & money. My mate sent a letter to the main base but no reply.
3rd time a store had opened in Stoke and I wanted a scanner. Once again I had the Manager on he phone and he confirmed he was looking at this particular scanner I wanted and said he would put my name on it. I got to the store (about 5 miles away) and my name was on a scanner but not the one I'd asked for

I told him this was the third time this had happened and after a while of me moaning he knocked £100 off it (this was when scanners were around £250 to £300).
About 10 years ago I walked in and saw my biker mate in there with a suit on. I asked him what he was doing and he was the floor manager

He was the security guard but had been promoted. He hadn't even got a calculator let alone a computer but had the gift of the gab which meant selling from what was on the sales card but he hadn't got a clue what he was on about.
I haven't used them since and he now works in a Harley Davidson repair shop where he doesn't have to bluff.