Depends how many people. If there's going to be hundreds, then probably the Ducie - which is bigger, but fairly strict on licensing laws. If there's not too many, then the JA - which, well, stops letting people in at 11 but....I think as I type. Hmmm The JA is easy walk from Picadilly Train station so for people arriving that way, it would be ideal.
It aint too big - but think how many we squashed into the front bar of your local, Bron!
17th-18th ish is fine for me.
Cheers,
Catrin