anyone know if there is much difference between a 105 and dura ace octalink 109.5 bb (for track dura ace cranks) apart from dura ace costing 3 times as much?
The 7710 bottom bracket has the NJS stamp on it, the 105 doesn’t.
The Octalink spline should be the same and the spindle length is the same so imagine they are interchangeable. 
i got an ultegra one in my cupboard you can have for cheap…