Do you know where I can buy a stable door in London to replace an external back door?

Your local Howdens Joinery . www.howdens.co.uk

There are lots of websites that sell direct and deliver and provide good quality doors. You just need to measure your existing so you can pick the right size when ordering. They will also help you if you prefer to speak to someone, just give them a call. I have bought many doors this way and never had a problem. Thanks Andy www.wood-chips.biz

MAGNET TRADE, SELL GOOD DOORS I HAVE ONE MYSELF 9 PANES OF GLASS

yes ive had 1 from howdens too . good price also