John Dyer writes
I'm a first-time tomato grower, growing some Gardener's Delight toms from
seed. I've got two pots of them sitting in the cold frame and they've been
doing pretty well; but this morning I noticed that a lot of the leaves on
both plants are looking mottled. I didn't have the chance to have more than
a quick look, but virus infection immediately sprang to mind. I'll try to
take some pictures and post a link tonight, but if it does turn out to be a
virus infection is it worth me planting them out, or should I get rid of
them (especially as I'm a bit worried they might spread something nasty to
the potatoes).

Have a look under the leaves and see if it's insect attack.
--
Kay