Here is a suggestion.
Poll your possible dates, say at least 4 weekends in Sept and October (the 2 you have planned and the first two weekends in October).
Give it a week or so and see what is leading. From there, suggest an evening bash too in the local town or even a flying club at the field. Make it somewhere with a relatively cheap hotel/b&b nearby and your on to a winner.
Post the fly-in here and the evening bash in the bashes forum mentioning both if you get what I mean.
I could be tempted for a pint up that way myself. Lovely part of the world. Lets see what date comes up and let the ppruners decide...!!