There's another firm in Evesham (Cotswold Parts, I think) who sell masses of spares like that on line who would be good for comparison. BUT firms like that have large and fairly fluid stock movements with plenty of storage and are usually happy to sit on stuff until it can fetch their minimum required price. To answer your original question, your stuff is only worth what somebody else is willing to pay for it and somebody willing to pay a higher price just might not be around in the timeframe that you need to get rid of it within (if there is such a timescale).