In message . com,
yitzak writes
The door is in good condition, was new a few years back and so has only
had one coat of gloss on top of the undercoat.

That's not necessarily a bad thing. Dulux recommend 2 coats of their
undercoat and one of top coat of their weathersshield paint IIRC.

A few small cracks have
appeared. Want to paint it again.

Do I need to undercoat it?

Yes. it's as important as the topoat

If so is it ok to undercoat with a white
undercoat and then paint it with black gloss?

If you want, but I'd use a dark undercoat as well.

Or can I directly apply
another coat of gloss seing as its in good condition

don't spil the ship for a happorth of 'tar...


Any recommendations of paint would be appreciated?

I've always been happy With Weathersheild. The trade one is bit better
probably, they do claim a longer life.
--
Chris French