Trevor wrote:
The experts will say it's the high July temps, however my polytunnel crop
sown at the same time as the outdoor ones have been fantastic and are still
on the go whilst the outdoor crop allways looked poor (French climbing
beans)

I'm tempted to say "not enough water". I also think that your indoor
ones may have had a higher humidity environment. I don't think they
like baking dryness., even with water at the roots.