I just replaced the cartridge with another new one, and the colours are still washed out (even after a few prints).

Hi Joanna,
Have you cleaned the cartridges? This can be done in the printing preferences of the printer (through control panel>Printers & faxes). Recently there seem to have been a surge of faulty cartridges from Primera. I know you've already tried a secondary cartridge, but if possible - try a third! It certainly sounds more like a problem with your cartridges than your printer. Hopefully you'll get the printer working fine.
let me know when you find one that works, and I'll authorise the return of the faulty cartridges. Kind regards, [edited]

Thanks for the reply, and sorry for the late response. I have tried a 3rd catridge as you suggested, which works fine. So I'm going to be sending 2 cartridges back to you for replacement once I receive a returns number.

Thanks for all your help, [edited]. I really appreciate it.

Hi Joanna,
I'll authorise the return now! Glad you got it working!
Kind Regards, [edited]

Hi Joanna
We will post you two replacement inks shortly.
Please note this ticket will now be closed.
Kind regards,
[edited]