Bretforton sounds good (and the barn has a good sound). I would be interested.
I also have an additional suggestion.
Whatever date / venue is decided upon we are not all going to be able to make it. So Yes to a Memorial Concert but why not a lot of others does as well.
For the rest of this year why don't we all remember Theresa in the way she would like best. At EVERY festival we have connections with, let's persuade the organisers to nominate one of the Sing-a-Rounds as the "Theresa Tooley Memorial Sing-a-Round" and let's all sing our favourite songs that we sang with T. That way every-one can join in somewhere.
Pass the thought on.
Jim