So I went back last night
With a variety of small levels and I discovered a couple of things:
1) The Hawke level didn't concur with any of the other levels. The ability to clamp onto dovetails is nice but it's not a lot of use if it flips up to one side when you tighten it the teensiest bit.
2) A simple acrylic level resting on the top surface of the action worked best (A pressie from the generous S. Edmonson).
3) The tops of the mounts aren't usefully level
4) Some twit had set the place on fire!
Reckon I'm all dialled in now, no crossover, ringing the bell consistently, not veering off to one side for the short ones.
Thank you all for your suggestions.