So, perfect 3 bike garage. 1: for track days (must be fast , reliable and not too expensive in case it goes down at Craners) 2: appreciating (at least not deprecating) classic for odd Sunday ride to coffee/bacon meet. 3: odd commute, general hooning, occasional few day trip round Europe. Go!
Its only got to get to the bacon roll shop twice a month. £5K will get you one all day long at Stafford Classic old UK bikes show.
I wouldn’t look past an 1100 monster either tbh, stick drop bars on it and it will be suffice to for most uses.
Not sure it would be fast these days (in my hands especially) or fit the "not to expensive to launch" part either.
Greeves Scottish ( occasional pre '65 trials ) BSA B31 (Gold Star replica ) Triumph Bonneville (Hinckley type) got 'em