Adrian C wrote:

How long does Sikkens normally
last in the glare of the unforgiving sun?

Tried it in Italy on a west facing window. Two years later it was
peeling off. I've since tried proper (two pack polyurethane) varnish and
that has lasted for five years so far. The other finish that has done
well is Brewer's own brand exterior gloss, used on an east facing door.
It does incredibly well in the sun, so well that Italian neighbours have
started to ask if I can take extra tins with me next time so they can
use the same paint.