Dell UK, XPS 13, Faulty SSD / WiFi / LCD / Keyboard, Refund/Replacement request

Hi,

Service Request Number: . I purchased a Dell XPS 13 in June 2013 from Dell Outlet UK. Unfortunately, the LCD, touchpad and keyboard replaced due within a few weeks as they were faulty, but they were promptly fixed by a technician. I have had issues with the WiFi card that is in this machine which I believe is a widely reported issue and have tried new drivers and all the fixes suggested online/from Dell but they have not helped and I experience frequent disconnections and slow speeds even when close to the routers. In October 2013, I discovered that the SSD was showing up as faulty in the Dell diagnostic tests as well as the 'Pg Dn - arrow' key constantly falling out. This was extremely disappointing for a high value laptop that has been looked after. My AC adapter was the next problem, as it was no longer charging, however I requested a replacement due to the number of issues with the laptop and the number of previous service requests. A refund was agreed, however there was no similar laptops available on the Dell Outlet website and to receive a new machine would have meant I would had to pay around £200-300 which I could not understand.
I was also informed that if I requested an AC adapter then I would not be entitled to a refund. I believe this was extremely unfair, as I needed the AC adapter as the laptop could not charge and was running at limited speeds making it un-usable for work. I have been in Ireland and busy studying since then, and have recently called to request a refund as I still have the same faults and not happy with the service I have received. I do not have the time or do not wish to have the laptop repaired again. I spoke to a technical support agent on the phone 4 days ago who asked me to send a photo of the LCD and they would pass this on and then process a refund. I was left a voicemail yesterday to ask me to email, which I did but received no reply, so I called in just now and was informed that a refund was no longer an option. What is Dell's complaints procedure in the UK, as I'm looking to get this laptop refunded asap but getting nowhere with technical support?

Thanks