Have a bit of an update. Did a dynamic balance as discussed. Unfortuately due to an "engineering fault" (aka human error) on the subsequent flight, a spinner screw came out and damaged the prop.
Replaced prop with a Sensinich 2 blade, still got vibrations (not looking pretty at this time). Decided to turn clockwise (anti-clockwise rotation) one bolt hole, many of the vibrations went away. Am thinking might rotate another hole and check for vibration reduction or alternatively dynamic balance in current position. Bit of a pain though moving it as it won't stop in the horizontal position now.