A good clean original looking MC21R I would realistically estimate £2000 - £2500? Looks really nice and original but unfortunatley for you its an R and not an SE/SP which are far more desirable and worth a fair bit more.

Stick it on ebay and you will see what people really think its worth opposed to over inflated prices shops have of bikes that have been for sale for months and not sold.

I guess the real question is.....what price do you value it at?