Tomato leaves discolouring... disease, or just dehydrated?

Hello. Please see these images...

http://www.flickr.com/photos/jamesbrownontheroad/3848122519/
http://www.flickr.com/photos/jamesbrownontheroad/3848122331/

... of some of our tomato plants. We sadly didn't give them enough depth of soil, but nonetheless have had heavy cropping trusses with small but tasty fruits from three of the 'turbo tom' grafted plants we ordered earlier this year from Dobies.

However, some of the leaves now have some yellowy discolouration. Have we just not been watering them enough?

I'm asking nervously, because although they are in our shed our neighbouring plot holder has seemingly allowed an entire crop of potatoes to become blighted, and this has subsequently transferred to other potato plants in other plots. Just afraid that our first year will be marred if our precious tom plants become blighted too

Thanks - and apologies if this over-reacting!

They look ok to me just old age catching up with them As long as you are watering and feeding the top leaves should be fine. Just remove any old crispy leaves