Identifying older PE pipes

[squowse]

There are lots of adaptors for the various older standards of PE pipe (LDPE, MDPE, HDPE).
Does anyone have any tips for identifying which adaptor should be used.
Pipe I am looking at at the moment is 27mm OD. So it's a 3/4" pipe but which one?
http://www.floplast.co.uk/uploads/downloads/Adaptors.pdf
There does not appear to be any writing on the pipe. I could measure the ID if that helps.
Thanks

 

[leakydave]

Your best bet if possible is to cut a short piece of pipe off and take it to either a merchants or to buy a larger bulkier universal transition coupling.

 

[Charnwood]

Presumably it is black water service pipe (Alkathene). If so, it will be marked every yard with size, class, BS number.

Philmac 3G fittings will fit it if it is black Alkathene without the need for adaptors.