Below are the links to the main websites for each distributor I could find - they should of course also be available thru normal channels (LoveFilm, Amazon, iTunes, etc). Bear in mind if you're ordering DVDs there will probably a good wait for delivery - even better perhaps is if you say in the notes with your order that you are in no rush - and to preferably buy a download/stream.
Update 1 - Brendan Connelly at Bleeding Cool is also building a good list - worth checking as it has direct links to specific titles that can be downloaded/streamed
Update 2 - Network DVD have taken their shop offline and promise it back within a few weeks. I'm not sure if this because of legal requirements to ship within 28 days of order, or if it will cause problems with their system. Either way perhaps a sign that it might be best not to buy DVDs from distributors before they've had a chance to either take off their shop or publish a statement.
Update 3 - Artificial Eye and Human Film also confirmed. The Bleeding Cool list has lots more direct links and other distributors.
Arrow - ArrowFilms.co.uk to buy DVDs
Artificial Eye - lost their entire 300-title stock.
BFI - has lost 120,000 units with lots to chose from. Get on DVD or preferably online at Jaman, BlinkBox or LoveFilm or get a membership to download films and more.
- distributor of social documentaries lost 50,000 units. dogwoof.com/itunes
for iTunes, for DVD club
(worth joining), Pop-up Cinema
to organise a screening and Dogwoof.tv
Guerilla Films - tireless supporter of British indies has lost 60,000 units. Guerilla-Films.com to buy DVDs
Human Film - producers of Aahlam and Son of Babylon
Kaledoscope - can't currently find a direct link to buy, but they will be on sites like amazon.co.uk
Metrodome - DVDs available to buy in subsites under Critical Acclaim, Epic Asia, Horror, Action/Thriller and War as well as normal download platforms.
Network DVD - lost all their stock and are not taking online orders until things are back to normal in 'a few weeks'. You can follow them on Twitter and Facebook for updates.
Pecadillo Pictures - lost 50-60,000 units. PeccaPics.com to get DVDs and iTunes links from their Facebook page.
Revolver - Revolver DVD/Blue Ray here, LoveFilm, BlinkBox and iTunes links here.
Urbanized Film - aka Gary Hutwist, director of Helvetica and Objectified. You can buy Helvetica here, Objectified here, and in the US get tickets to the new film Urbanized here.
Meanwhile there were over 150 independent record labels using PIAS distribution - including Domino, XL, One Little Indian and Warp whose stock has been destroyed, leaving companies 'devestated'. There's a list here - http://thequietus.com/articles/06729-help-riot-struck-pias-buy-mp3s