We have the following left;
Luton, Swansea, Stoke, Watford, Sheffield Utd, QPR
I would think that all those except Luton will be above average away attendances.
As for the North West clubs, some are within 20 miles of each other or at least an hour or so, meaning less time and expense to travel, so their away attendances are skewed in that respect. I think PNE took over 6k to one of their local away games..