In message , Mr Fizzion
writes
What's the reason for the diameters of MDPE pipe and why are they
different to copper?

And another one: why is a street elbow called a street elbow?
(The rather low quality article on wikipedia was of no help!
http://en.wikipedia.org/wiki/Street_elbow)

Last question: where is Doctor Evil? :-)

Back, unfortunately

It would appear that the brain transplant was unsuccessful, and the
jury's still out on as to whether the gender change worked.

--
geoff