Thank you for your thoughts, it has got me completely baffled. If I could work out what was imprinted on the base it would be a big help, but it just looks like a big stick or tower surrounded by waves to me. I wondered if it could be a trial piece because the strapping is very fine and brittle and the base is a bit wobbly. The colours are consistant with phoenician glass, but their bases are usually ground, polished and signed.
Thanks again for your help Penny