Do UK Smalltalk User Group has any legal status?

[Юрий Мироненко]

This year ESUG conference will take place in UK.
I am Yury Mironenko, I'm from Russia, so I need a visa to get into the UK.
It looks like I need letter of invitation from UK organization (or organization with UK address, I'm not yet sure). UK Smalltalk User Group is listed as one of conference organizers this year.

So:
* do your group has any legal status?
* if so, do you have something which can be called "UK address of organization"?
* if so, do you have seal/stamp of some kind (which can be used to seal the invitation letter)?
* if not, maybe university where conference will take place, have one?