How much is this laptop worth?

[Lapetos]

Hey all, long time no speak.
So looking to sell my laptop that's in my signature so that I can aim towards a GTX 980ti or the new Fury GPU.

Bought the laptop February last year for £1800 from PCSpecialist.Co.uk which I know would of been slightly overpriced.
I'll paste the spec from the order itself.

Chassis & Display: Vortex Series: 17.3" Matte Full HD LED Widescreen (1920x1080)
Processor (CPU): Intel® Core™i7 Quad Core Mobile Processor i7-4910MQ (2.90GHz) 8MB
Memory (RAM): 16GB SAMSUNG 1600MHz SODIMM DDR3 MEMORY (2 x 8GB)
Graphics Card: AMD® Radeon® R9 M290X - 4GB DDR5 Video RAM - DirectX® 11
2nd Graphics Card NONE
Memory - Hard Disk: 960GB CRUCIAL M500 SSD, SATA 6 Gb/s (upto 500MB/sR | 400MB/sW)
DVD/BLU-RAY Drive: 6x BLURAY ROM, 8x DVD ±R/±RW & CYBERLINK SOFTWARE
Memory Card Reader: Internal 9 in 1 Card Reader (MMC/RSMMC/SD: Mini, XC & HC/MS: Pro & Duo)
Thermal Paste: STANDARD THERMAL PASTE FOR SUFFICIENT COOLING
Sound Card : Intel 5.1 Channel High Definition Audio + SPDIF/MIC/Headphone Jack
Bluetooth & Wireless: GIGABIT LAN & WIRELESS INTEL® AC-7260 (867Mbps, 802.11AC) + BLUETOOTH
USB Options: 3 x USB 3.0 PORTS + 1 x USB 2.0 PORT AS STANDARD
Firewire: 1 X 1394a FIREWIRE PORT
Battery: Vortex Series 8 Cell Lithium Ion Battery (5,200 mAh/76.96WH)
Power Lead & Adaptor: 1 x UK Power Lead & 230W AC Adaptor
Keyboard Language: INTEGRATED BACKLIT UK KEYBOARD WITH NUMBER PAD
Operating System: Genuine Windows 8.1 Professional 64 Bit - inc DVD & Licence

I've had a guy from eBay wanting to know how much I'd be willing to take cash price straight away. It's currently bidded for at £600 and really am clueless at what to say to the guy.
Any rough estimates as to it's worth?
UK based.

[Deleted]

I have no idea how much it's worth. But you should be careful if you cancel an auction that already has some bids on it.
I don't know how the legal situation in the UK is, but here in Germany the highest bidder can drag you to court if you cancel the auction without a good reason.

[Lapetos]

Bid randomly got retracted now anyhow. So that would no longer be an issue (2 bids got retracted I noticed which is a little weird, although maybe due to some lesser spec gaming laptops just been posted and an Alienware one too)