The 80 amp fuse is located on top of the Sevcon controller.
see the middle photo - that gold coloured thing is the 80 A fuse.
I've done about four of these conversions. We can buy the CALB cells cheaper, but there are more hours in putting it together. Much of a muchness really.
The blue scooter has done about 10,000 km on lithium so far, and never been a problem.