Tough question. Some shops might others might not. The tanks are not "CE marked". This marking is to ensure that personal safety (or life support) equipment is of a suitable quality and not cheap Chinese rubbish that will kill you. This marking is not required outside the EU and so US kit is not CE marked but it is nevertheless without doubt of a high quality and safe.
You can buy Ali 80 and Ali 40 tanks in the UK (they are popular with technical divers as stages) and tanks that were made before the CE marking can still be used. In fact the CE marking is not law and only applies to professional divers. However, some dive shops take the view that their staff (the tank filler) should only fill CE compliant equipment. To add to the problem a new CE system has been introduced for nitrox with a new cylinder valve dedicated to gasses over 22% O2
In short the only way to answer your question is to ask the dive centre that you intend to use. As to the hydro test again the law is unclear. The UK dive tank testing is done by IDEST and they might take the view that the tanks are not CE tanks so cannot be tested. This (again) is not law, but if the guy at the dive shop says "no" the law is somewhat irrelevant.
Tanks are not expensive in the UK and are 232 bar as standard (3500 psi). The standard tank is 12L so a little bigger than an Ali 80 and they cost about US$220 new. test cycles are 2.5 years visual and 5 years hydro. Oxygen service is annual. O2 cleaning about 40 dollars. Most UK centres require O2 clean tanks for nitrox. Hydro test about $50, visual about $40. Mostly you get a valve service even if not needed - about $20.
Tank rental about $15 a day.
Tanks
must have a content sticker and some dive centres get
very silly about all these regulations others do not. Not much diving near Mildenhall - head south and the channel for the good stuff. Not sure there are any centres there for filling. Ipswich is the nearest and has opened a while back but after I lived in that town (I was at college there).
Depending on how many tanks you have I would be very inclined to sell them and buy European specification tanks. If you want to find out about the dive centre in Ipswich and their views on your tanks they are here:
http://www.diveline.co.uk/
Tank regulations are a bit silly in the UK right now. Mainland Europe is better
Chris
