OK, I've read everything there is to know about the subject on t'interweb
and I'm significantly more confused than when I first started.

Blank canvas - new bathroom - no earth at present. The ceiling is 2.9m high
and the lighting is 12v IP44 rated with an external switch. There's nothing
else electric in the bathroom other than the extractor fan, which is double
insulated.

I have a metal bath, metal towel radiator (NOT electric), metal shower and
(obviously) metal taps. All supply and c/h pipework is copper, all boxed in
above floor level, and the mains water supply to the building is plastic.
SO...

1. I gather I need to earth my lovely chrome towel radiator with an awful
green and yellow cable? How on earth (sorry!) do I do this without having
the earth cable dangling up my wall? Would it be sufficient to bond the
(microbore) pipework inside the boxing (approx 1ft below the towel radiator
itself) or does the actual towel radiator need to have an ugly earth clamp
stuck to it?

1b. If my towel radiator MUST be bonded, why doesn't it have a strategic
point onto which to attach an earth cable?

2. I read somewhere that if the earth cable is within conduit 4mm^2 is
sufficient. Since the earth cable will run (loose) within boxing around the
room, does this count as conduit?

3. OK, so I connect everything together with earth clamps and bits of
wire - where does this ultimately need to go back to? I've read it's NOT a
good idea to take this back to the CU.

4. If I bond everything together within the boxing, to hide unsightly earth
cables, will this be sufficient? (the boxing will have removable panels at
strategic points) i.e. exactly how close to the taps, towel radiator,
shower etc. does the earth wire need to run?

Think that's it! TIA,

Andy