Hi John
Thanks for taking an interest in my issue!
I really can’t see how it can be caused by location rules. I have checked again and the rules are as follows:
Post Type is equal to Gallery and
Post Category is equal to Elvington
Gallery is a custom post created in code by me – and as I have said before the other Galleries work – the Rules for those galleries are exactly the same apart from obviously applying to another town in the drop down