Great post, @neumannsalva. I wonder whether you could get in touch with Tilly and the Buttons to see if they can suggest how to sort the problem?
You did a great job and should be proud to be wearing a 'me-made-may' skirt ! - oh and you even got chocolate cake !! :D
I have never thought of this... hmmm... contacting the designer. I am not sure, but I guess my sewing qualities are still not good enough and they could always blame me for this (and perhaps for choosing the wrong size) But on the other side I like the idea very much. Perhaps they could recommend a clever hack and than everything fits perfectly ...