Sorry to hear you're having trouble. Having experienced my fair share of UK retail customer service, I can sympathize.
Not to hijack, but in the spirit of "misery loves company" we went through a similar situation with a couch we bought from Home Base. It was an L shaped couch that was supposed to arrive in 2 pieces. It took about 8 weeks or so to deliver it, and when it arrived, they brought 1 piece of the wrong L shaped couch. Because it was all wrapped in cardboard and plastic, we didn't realize it was wrong until the delivery guys had left (they rushed out like they'd robbed a bank).
When they finally brought the right couch a couple of weeks after that, they refused to take the wrong half couch they'd left the first time. My wife had to get on the phone with the warehouse manager, who convinced the driver to take the wrong half couch away.
Two months later we noticed the leather was wearing away from the couch at the seams. Home Base sent a guy out to inspect it, and he agreed that it was faulty. As it had been discontinued, there was no replacement, and they agreed to refund our money.
They made arrangements to come get the couch, and when they arrived they insisted they were supposed to exchange the faulty one for a replacement that was on the truck (discontinued?). My wife called Home Base, who told the driver to just take the couch and not leave the replacement. Unfortunately, he didn't have room on the truck, and had to arrange another truck to come get the couch.
The final annoyance was once the couch was gone, Home Base wouldn't refund our money on the phone, we had to go to the store.
Anyway, again sorry to hijack! You're not alone!
[edited to add] And to add something positive, we bought a sofa from DFS, and they've been brilliant. It took as long as they said it would, they called twice along the way to let us know everything was still on schedule, the delivery guys came when they said they would, set everything up, and removed all the packing stuff. Well done, DFS!
