®óñ© © ²°¹°-°³ writes:

You could google for Epsom Salt treatment. Shouldn't do any harm
even if the answer lies elsewhere.
Get some good proprietary tom feed on them as well.

Cheers, I'll give 'em a feed and hope for sunnier weather. As to a tomato
feed, I've got some courgettes and beans on the way at the moment, sill a
bit small but growing. When the time comes to get them into larger
containers, will a tomato feed also be appropriate for these?