I've read a lot of useful information on this forum in the past and am asking for a little guidance on my digital piano.

I have a Yamaha CLP860, about 4-5 years old. It is in perfect condition. I am looking to purchase a CLP170/270 with the more authentic keyboard. Anyway, I am finding it difficult to approximate the value of my 860. I live in England, is there anybody that can give me an accurate resell value?