Finding Roman coins isn't much of a problem. They found several at Newgrange in the excavations. The Romans, as we know, looked at the religions of the countries they kicked the shite out of and adopted many of them. Many of the big sacred sites of the time would have been visited and honoured by thr Romans and, more importantly, the Romano-Britons. If you find a Roman coin at a site it just tells you that it was still sacred during the first four hundred years CE. Obviously where it is in the stratigraphy (is that a word?) is the key to knowing what the presence of a coin really means for a site.

I need to go and wash my keyboard now after writing 'R*man' so many times!