I have a "Next" sourced monobloc tap that has been iffy since I bought it. About 5 years old.
It has always been difficult to put the lever in a position that stops the water flow. It failed.
I am looking for a UK supplier for a new ceramic cartridge. Part type: "MAM Joy 35".

Macker, March 2010

I got one from Lunns via website. Cost £35 including delivery. Had to remove old cartridge and measure it to find nearest fit from Lunns offering. Fortunately I got it right. First part supplied was faulty but had no problem with Lunns exchanging it. Cheaper than new tap assembly.

Macker, April 2010

best of luck, us plumber have this problem all the time, so we offtern fitt new taps.

erj, March 2010