Topic: 18th century air twist ale glass

[markhig62]

Hi all
I recently bought  this ale glass (described as 18th century) having viewed only relatively poor photos. Having received it, I still believe it to be 18th century (around 1745-50). It has a grey hue and is lead metal. The bowl has clear striations and pucella marks (I haven't managed to show these in the photos). There are marvering lines on the short plain stem section and feint ridges can be felt on the air twist section. The foot is domed with a flat top (helmet foot) and the section of foot outside the dome is gently conical (not flat). There is sadly a small flake chip to the bottom of foot rim (but I don't think I would have been able to even dream of buying it if it had been intact). The foot rim has good mossing. The metal has some small inclusions and very small air bubbles but is generally quite pure. What do people think? Am I right in thinking that it is 18th century or could it be later?
Looking forward to some opinions and hoping for Peter's too!
Cheers
Mark