For what it's worth I've never
seen a semi-raised or raised pontil in conjunction with the tooled in/pushed in "P". Surely it would not allow for the "P" to occur, since it covers the area where it should be?
My monies on it being Perthshire Paperweights. It certainly has the attributes of those pieces that have swirls, with two colours and the canes between. There a number of known examples of these, but not in this cylinderical shape - so, maybe
, there's a first
However, I've never studied the canes in the way that you do Kevin and they may be the conclusive evidence that is required.