My favourite way to make a filtered value list doesn't involve relationships at all. Perhaps you could try this. Create a calculation that will return the shop name only if it's active. Then, build your value list based on it. Of course, ultimately, you'll probably want a 2 field value list, in which case your new calculation field will be the 2nd field.
That works a treat and keeps overheads down. Nice and simple.
Glad to hear Peter;
Just remember that this technique will only work when your calculation can be stored. Whenever your calculation becomes unstored, it can no longer be used in a value list.
Thanks again Matthew,
Funny you should mention that. I just wasted a few hours attempting a work around on a relationship for that very same 'unstored" reason. I'm doing some serious grunt work so easy to overlook the basic rules when you are doing bulk.