Picture posting is enabled for all :)
I would say feed them. I bought some very yellow specimens from B&Q for 50p and within a few days they have greened up nicely with a few doses of nettle tea.
All good advice and helpful tips . Hopefully Tas's tomatoes went on to produce a great crop, (thread was first posted in 2012)I just noticed a couple of my tomatoes looking a little yellowy, sprayed them this morning with Epsom Salts.