You are right Wade, I should have expanded upon the plastic. I sold Polyethylene Pipe (Plastic) for a living and the Polybutylene (containing Bisphenol A, or BPA), can possibly cause problems, if I am not mistaken because this all came about after I had left the business, it was the possibility of problems with reusing the bottle after the VU rays had caused degradation to the original molecular structure and this had the possibility to damage developing unborns? But that was polybutylene.
When looking for plastics, always look on the package and see that it is Polyethylene and its molecular density. Its easy and always clearly stamped in the plastic. Milk jugs, clothes bags, pipe, auto bumpers, hula hoops, every polyethylene product (and there are a lot!), carries a stamp of either HDPE (high density Polyethylene), MDPE (Medium Density), LDPE (and Low). HDPE being the heaviest, its obviously the best for strength and durability.
And I apologize for not being so clear its been awhile since I did any international research but when England first started developing its poly industry they were as well regulated and better policed that the US.
I believe that all the Bisphenol A or BPA products have been removed in the US which would lead me to assume the same in England, its all probably been passed on to third world countries where lawsuits are not a way of life.
FYI, NSF (National Sanitation Foundation), certification only means that the pipe at one time went thru the testing process to meet the standard, its expensive, so it was a way used by the big manufactured to help limit the competition. The same with ASTM The standards supposedly set by industry, AWWA Water works, etc....
LOL... dang there I go again rambling.
Basically look for the Polyethylene stamp and you'll be ok.
Here we go, quick and easy:
http://www.wikihow.com/Identify-Food-Grade-Buckets