Robin wrote:

I've read the thread as pointing to either copper soldered to lead or a
lead-lock; and you can use lead-locks to plastic pipe (with insert where
appropriate).

The lead-loc plus range P/N DP200x are for MDPE rather than copper

http://mr-lead-loc.com/Lead-Loc-Plus-Range-C273408.aspx

sizing/fitting instructions in case Roland wants to keep an eye on
whether his plumber is doing it right

http://www.melimatic.com/4.html