Advice Needed - Logic Board Faulty - Where to Sell

Hi guys, I'm not if this is an appropriate question for this site but I am really at the end of my tether with this laptop and seeking some advise on the best way to get rid of it.

I purchased this early 2011 15" MacBook Pro second hand of eBay from a company called ckit computers in 2013. Of course this turned out to be a huge mistake... Like many similar 2011 models it suffered from GPU issues. After taking it to an Apple Store I found out that it had a replaced logic board and would not be eligible for repair at any cost. At this point I thought my best option was to get the GPU reballed at the most professional company I could find. I chose Mac Guys who did fix the problem however in the process of returning my laptop smashed the glass over the screen. Months later they returned it fully repaired and I had a fully functioning laptop for just over a year until now where it fails to boot half the time and appears to have the same GPU issue. All in all I feel like a right mug and will not be buying from anyone but Apple in the future and at this point want to recoup as much money as possible to finance a new laptop.

How do you think I should go about selling this laptop and where would people recommend? I assume my option is either as an entire faulty machine or individual parts. As most of this laptops life has been spent as a paperweight most parts are in very good condition. It would be great if anyone could estimated a fair value for this machine.

Logic Board - i7 2.0ghz with 256MB AMD graphics (fauty can be repaired by resoldering)

Display - LCD is working and still clear with no issues. The glass panel has been replaced

RAM - 2x 8GB sticks working well

HDD - Did have a 1tb but I would prefer keep this and put it in a usb caddy.

Trackpad and Keyboard - clean and working perfectly including backlights

Battery - still holds a reasonably long charge

Case - slight dent on the dvd drive side but other than that clean and usable

DVD drive - broken

Fans - still working smoothly.

Any advice on how I should sell this laptop would be appreciated (note I am living in the UK)

Thanks in advance! Hopefully I'll be able to close the door on this laptop that has brought me nothing but disappointment :)