What did you pay for the set up, boat, trailer (engine?)?
Add it up, have a look at previous ebay sales of similer craft (or search the for sale archive on here) and if the two are about the same then that's the answer.
Pete on here is a good one to ask, he also does brokerage sales
I sold my 3.83 Yam with a bunked trailer and 25hp engine for £1400.
PS - is that Thornbury in Devon?