So it turns out Photoshop has the exact function I was talking about; if you add 2 layers in and then set one to "difference" it shows you everything that has changed between one layer and the other in white, and things that remain the same in black. Thanks to the lack of movement we can see the numbers bleeding through:
The 9 is the biggest stretch of the imagination, as unfortunately it is almost completely lost to the background image. But given the rest, I think it's safe to assume it's a 9. Does anyone know what font it is being used? It'd be great to be able to overlay actual text on the images to confirm.
Once I've finished doing these I'll go back and do the clip from yesterday and see if there's anything to be learnt from that.
EDIT: Frick sorry double posted.