what I'm after is a decent light touring frame, as opposed to a twitchy pure road bike. This might even have a triple already.
Whatever transmission, downtube shifters are on the agenda. Touring heritage would probably also give it the ability to carry mudguards. So, a 531 touring frame, capable of taking 700c wheels and relatively modern transmission, ie 48-38-28 up front, and something fairly wide at the back, 7 or 8 -speed.