I believe if you are selling "art prints" you will not have any problems from the Heritage folks. If you try to sell images for "commercial use", however, you can have big problems.

Plenty of photographers worldwide have sold images from Kylemore and other Irish sites as fine prints without raising any eyebrows. If, however, you want to do a shot for Guinness, then there's going to be some discussion.

I think it all comes down to the difference between "fine art" and "commercial." I shot at many sites with tripods, large format, etc., and was never asked about it by anyone.