On 11/11/2019 14:30, David wrote:
Having bought a hole saw and arbor from Screwfix and put them together in
what I think is the correct configuration I was frustrated by the fact
that the pilot drill was barely longer than the depth of the hole saw
which made it very difficult to align it with the mark for the centre of
the hole.

Don't try and drill on the mark with it. Use a separate drill or use the
arbor and pilot drill without the hole saw first - then you've got a
positive location for the pilot to locate in.

SteveW