There might be more of a responce if it was on a weekend as not everyone is on maternity yet, i will be on them days but most people in the 1st and 2nd tri wont be.
There was more responce to the original post for London or closer to London TBH.
Also i dont think many Moms to be or TTC'ers will want to spend the day in a childrens play centre without a child.
I think they went to all sorts of places at the last meet including a little animal place which people would be happier doing without children, And with a baby you wont really be able to sit and talk in a different area if they are in a play area because they will need constant supervision.
Hope this helps abit
cas x