Thanks everybody. Judging by Tootles book, it looks as if I have completely planned my veggie patches wrong this year and should have been armed with The Companion Garden last autumn when planning what to do. My brassicas are in the bed next to tomatoes and the tomatoes have potatoes on the other side of them. I have sown some marigolds (do they have to be French ones?) to go with my runner beans to keep off black fly and some nasturtiums to put with my broccoli and cabbages. I read also somewhere that cauliflowers do not do well with broccoli and cabbages.
Re Sweetcorn - is it really practical to grow s/corn next to runner beans, given that they are both tall crops? Thinking about the light aspect for each. I had wondered about growing them at right angles to runners.
All so mind boggling!