London in September - need some help!

Working on a get together in London in September (I know it's some months away) but would like to narrow down some details.

We would meet on/near Jermyn Street in the early evening. Would you like to meet at a shop and then go on to a pub? Or just meet at a pub?

If a shop - any suggestions? Any contacts with shop owners?

And/or if a pub, which one(s) would you suggest?

THANKS