I've buried a meter or so of heavy gauge steel conduit in a brick wall
to bring some lighting switch cables to a switch. I had to route them
in the back of the wall behind tiles and the accessory isn't visible -
it's on the other side of the wall. It's clearly under the tiles in a
zone 1 area. Of course this doesn't make it 'in zone 1', but there may
be dampness eventually.

1) Do I need to bond this? The plumbing (basin and loo) is going to be
plastic.

2) As there isn't anything to bond it to, I'm tempted to connect it to
the CPC for the lights. That way any wally drilling through it (by
golly this brick is hard!) will have his drill bit earthed before he
hits the live. Is this allowed?

R.