Is it a JV badged 'Squier' or a JV badged 'Fender'?
The very early ones were still badged Fender and are worth a bit more than the Squier ones.
Black is a bit less desireable than sunburst, so you may take a few quid off for that - but I'd agree that £550-600 would not be an unreasonable price to expect - don't forget the Evil Bay fees will eat up 10% if that is the way that you decide to go!