Hi Clash

Canmore mention a carving at the end of the entrance passage. Don't know if it's the same one.

"There is a complex carving on a recumbent stone slab at the end of the entrance passage, immediately inside the broch. The carving is of a bar, 19cm long, 9cm wide at one end, and a figure of eight at the other."

http://canmore.org.uk/site/47004/torwood-tappoch-broch

Looks a nice broch.