[applejack]

several allotments at my venue are experiencing pale blotches on brassica of all types, is this weather related or something more sinister ? any help would be appreciated

[Yorkie]

Welcome to the site 

Sorry to hear about your brassicas.  I don't know the answer I'm afraid.  Any chance of a piccie?

Also, could you add your general location to your forum profile in case it's a localised issue?

[GrannieAnnie]

Could be sun scorch.  Rain on the leaves then sunshine?

[Mark-S]

Is it on the upper or underside of the leaves?
Any circles around the area?
How large are the areas?

Any chance of a picture?

Mark