Sites that allow metal-detecting?

Hello everyone.

My young grandson and I like to metal detect. We've been lucky on occasions to obtain permission to detect on a site or two where we've stayed with our motorhome. However, it would be better to know in advance which CS/CL site gives permission for this pastime so that we can arrange our itinerary to fit.

Is there a way of finding out who allows this pastime other than having to telephone or contact a site first?

Has anyone else detecting whilst camping and if so could you let me know what site it was? (Preferably farm-based sites and not big commercial ones)

Many thanks,

Bob