Chris Bartram gurgled happily, sounding
much like they were saying:

Primer isn't waterproofed - so if you don't get it covered over, water
will get into it and you'll end up having to sand it back and start
again.

Probably be ok if you warm it to dry it thoroughly. After all, you
wet-flat primer...It's a big problem with metal underneath though, as it
rusts.

Pffft.

The new screen surround and rear valance put on the Acad last spring have
been absolutely fine left in primer through the winter.

Which reminds me - I must order some of Screwfix's finest fiver-per-litre
red lead oxide, and some more cheap brushes.