At the end of the day of course it is only worth what someone is willing to pay, but I think this 50%+ off for a new frame would be aiming a bit low.
Assuming, we are talking of the HT carbon frame, then I expect a comparable 2011 frame could be had for around £1300 (Scott Scale 20 is £1350).
This would suggest less than £650, at this price I would expect people to be biting your hand off for it. Given it is not the current version and comes with no warranty will clearly affect the price. If it were me I would probably be happy with about £750.
You don’t need half a dozen buyers willing to buy it just one serious one.