hi gasit do bottle refilladaptors for their bottles http://www.gasit.co.uk/index.php?_a=category&cat_id=2
these dont have any pigtails etc . seems a resonable bit of kit .
i imagine they are approved by someone .
They have 80% cut-off valves and are as you say a reasonable bit of kit. The problem with filling these (or any other approved cylinder) is that unless they are trained to spot the difference filling station staff can't know whether they are OK or not. For what little extra it costs a remote filler kit with the filling point on the outside of the van makes life simpler.