Having looked at the Cuprofit specs
(http://www.britishmetrics.com/pdf/tech.pdf)
I note that they do not maintain earth continuity. How can I tell if my
pipework
is supposed to be earth bonded?

Well, you might not need to bother earth bonding. If you do, then it is
easily achieved with 2 earth clamps and a bit of suitably rated earth cable.
Personally, I'd be inclined not to, on the "isolation is safer than earthing
principle", especially if RCDs are installed.

However, I would still supplementary bond in a bathroom where required, as
the isolation provided would be insufficient to assure the local
equipotential zone.

Christian.