mixing tomato plants

got johns allotment guide..brill.. on page 233 says not to plant 2 varieties
by each other. does anyone else grow different varieties together in
greenhouse,i have in past but the odd ones did,nt do well.got 2 varieties
to plant now..need help

p 233 is in a chapter called 'Saving Your Own Seed', so the advice for not planting 2 varieties together only applies if you are saving seed for next year

It will not matter at all if you are growing tomatoes only to eat........I grow loads of different types side by side each year, as I try to find that elusive 'best tasting tomato' 

Yep thanks for tha clarification.  It didn't occur to me to actually go and read the book first.  I am only growing to get tomatoes this year, I am not worried about saving the seed, I'll just buy some new different seed next year to try.