Django's www.djangomusic.com

This retailer is based in the USA, but it is cost-effective to use them for delivery to the UK, particularly while the dollar is weak against the pound. Huge catalogue although not all items available to buy. Some very good prices both second-hand and new. Second-hand items ship from multiple locations where necessary (they have a number of real shops which hold stock) at no extra cost -- this means that you can minimise shipping costs by making a large order, yet CD's come mostly in ones or twos and are treated as separate orders, so no customs duty/VAT payable. Shipping costs are reasonable, free shipping offers sometimes available.

Delivery usually quite quick for international (1-2 weeks), and customer service is responsive.