In the past I have tried We Buy Any Car three times for quotes and every time the quote has been a p**s take !! and I have read of hundreds of others being given similar insults as quotes, I personally wouldn't give them the time of day.
Other than that I would say that Oneman has given you some very good information and advice and from a quick bit of research myself I would say that the £2900 bid that you achieved previously was a good offer and I would expect you to receive offers of between £2500 and £3100 maximum.
If you are looking at buying a brand new car then it may be worth seeing what the dealer will offer you in exchange, as some (though not many) may give you a reasonable deal to clinch the sale of the new car.