Finally found one for a good price...I bought it sight unseen.
How I got it: I emailed the guy that runs coppercorner about one he sold that cropped up on this forum and struck up a conversation. He was very encouraging (try and get the next generation into collecting so his business remains viable!). He recently got a new lot in and was sure to look out for the token I'm after (two issued by my town in the 18th century, one scarce and the other really rare). He found several of the halfpennies but made me a good deal on a nice old cleaned one (just £18 shipped).
He also found a 17th century issue, but it was a bit pricy to be bought unseen (from the description, its not one of the more interesting ones - but it had the town's modern spelling on it).
Should receive it in a week or so.