When we require a laser toner urgently in work, we go to Cartridge World in Birkenhead, and they give us a swapped one on the spot (refilled (re-manufactured as they call it) and take the old toner off us). They are by Tranmere Rovers, just down the road from the Halfway House.
Their number is 608 5522 (on a toner I have next to me). The store/franchise number is 9663?
Having said that, personally, I purchase HP cartridges off eBay and have done for years, the official ones can be bought at a fraction of the price of the shops (as little as £5 for black and £7 for colour), and Tesco do refill kits for £4 for black, and £5 for colour iirc, you can get em at the Tesco store in Brom.
Although tbh, I bought a Brother laser printer, and hardly ever use the HP Photosmart now lol - the toners on laser last for yonks, and 20 pages a minute for crystal clear black text, an inkjet just can't compete haha. You can even get laser toner refill kits off the bay though tbh, my toners are £16 a piece for 2500~ pages, so thats not even really worth it!