I was wondering about the 28th? We've often done Thursdays, but there's no way I can do the 27th, the 28th is the day I have to do two talks in one day but after that I'll finally be free come the evening so that would be viable though the concern/downside is that I might be knackered.
I think the main alternatives would be Tuesday 25th, just before I run into conference madness, and Monday 31st, but I suspect a Monday pubmoot wouldn't be well attended (I may be wrong).