Hi Steve, black eyed peas, {vigna unguiculata} is actually a bean, not a pea, it was originally in the genus phaseolus, but is now in the genus vigna, peas are in the genus pisum, they're grown in countries with high summer temperatures, so not really suitable for a british summer, {usually cool and wet}.
If I was you I would give these a miss and go for something a little less exotic, Derek.
ps, sorry it's taken so long for you to get a reply.

Hi Derek
Thanks for your reply I was thinking the same but I may have a solution. I have a 20ft polytunnel would they grow in there
Steve

Hi Steve, well it would certainly be warmer than outside, whether it would be warm enough would depend on what sort of summer we get, if we get a decent summer a poly tunnel would probably be warm enough, so if you really want to grow them, give them a try, if it doesn't work out you'll know for future reference, good luck, Derek.