1984 XJSC 3.6 Fuses RHD

My 3.6 1984 RHD UK delivered XJSC air-conditioning stopped blowing and I immediately checked the fuse to find that a 50 amp fuse was fitted as specified on the fuse box cover. This had been the case for some two years and was still intact. I then read up the hand book and Workshop Manual to find that RHD models require a 10 amp fuse – the hand book states that the fuse as noted on the fuse box cover should be inserted.

I have found a connection that had come loose driving the blowers – now connected.

I have been advised that there is a high risk of fire with a 50 amp fuse used in place of a 10 amp fuse.

Question is – why is the RHD a 10 amp fuse and the LHD a 50 amp fuse and why is my fuse cover contradicting the manual

Would be grateful for some guidance – Evan