In my opinion, you are better off going and seeing for yourself.
What one person considers a good market may not be what you are looking for. Every market day is different, even in the same market, and what may have been a good store market for buyers last year will have completely different entries in this year.
The supermarket buyers are not buying everything because they have quite tight specs to work to, so there is invariably something left for the small buyer.
So, if the market on 28th Aug is likely to have what you want, then go and have a good day out. Time spent in reconnaisance is never wasted.