Well, I made my twitter bot. I can post the python source, if anybody is interested (and promises not to laugh at any rookie mistakes!
It does a search for pro or anti EU hashtags, removes any duplicate and previously used users, then searches each remaining user’s last 20 tweets and if 3 of them have the hashtags in, it adds them to the tweeting list.
It then takes one user from the pro and anti lists and sends them a message asking them to get together.
Unfortunately, it seems to have violated the Twitter API’s T&Cs so they’ve suspended the write privileges. (scuppering the whole thing!)
Shame, as I worked quite hard on it, and really liked the idea. I got 5 replies, none negative, most amused.