London will always be the exception, but given the number of user groups already held in Bristol that manage to get around 50-100+ people in a month with ease I

London will always be the exception, but given the number of user groups already held in Bristol that manage to get around 50-100+ people in a month with ease I think that Bristol would be the natural choice outside of London. Whether a HN meetup would be successful or not is another story. It'd be entirely down to who would choose to organise it and what they could offer to local HN members.