Seems to be the current trend with a number of places selling both new
and used cars over the internet. No site of the vehicle they just
deliver it when you agree a deal.

One or two of the ones I've seen have offered very good prices, just
wondered if anyone can recommend any?

Ones I've seen are:-

www.regvardy.com
www.whatdealoncars.co.uk

and no - I've no connection with either site !!!!