Finally getting to fitting the sink in my d/stairs bog. The sink is a
B+Q 'to go' cloakroom job with a single tap hole while the tap is a
mixer supplied with a Hyco vented water heater (looks like a monobloc
but the hot control lets water through to the heater, displacing water
from the heater unit).

Anyway, the hole in the sink is slightly conical at the top, while the
base of the tap has a rubber O-ring. When I tighten the bolt that
holds it all together, the tap slips out of the vertical into the
dished/conical top of the hole, so won't sit straight. I don't think
there's anything missing from the kit - it's more likely that the B+Q
sink is carp - and the only way I can see to keep things right is to
put something between the tap and the sink to stop it, for example a
flat plastic washer. This looks like a bodge, even though the washer
is translucent, but I could try trimming it once the whole thing's in
place. Alternatively, I could be missing something here so I thought
I'd post and ask if anyone had come across this problem and had a
better solution.

All the best