The message
from Kay contains these words:

Stewart Robert Hinsley writes
OTOH, for gardening purposes, the direction of the sun at midday is
probably close enough - unless you're setting up a sundial.

If you're setting up a sundial, isn't enough to wait till the sun comes
out, and then align it so it shows the correct time?

If you're setting up a sundial in the UK, do it in summertime after
the clocks change. Then it will tell you the right time when you're most
likely to be outside, and in sunshine) and will be one hour out in
wintertime.