Thanks David. I was thinking Spanish tourist glass or old English glass.... but without a clue really. A GMB member has suggested to me it may perhaps be English 19th century from an unofficial non-registered glass-maker, making utilitarian ware, bottles etc. not clear glass. Apparently almost impossible to identify, if so. The photos are not great I took them in a hurry. The pontil rod mark is not sharp. This piece belongs to a friend so any information I can find will be of interest. I am pretty sure this is a drinking vessel of some kind.... but exact attribution seems a way off!
Robert (bOBA)