Hi Gents. Thank you for the replies. I tried Drewpy's advice, but it's not even hinting at moving. From what I can see, you'd need a pair of seriously strong hands to win that struggle.
The larger of the two tools suggested by Slice may do the trick. I don't have one however... I'll be looking out for one. If that doesn't work, then I'm stumped. I can then only hope that my local Yamaha dealership will have a solution.
I'm in Cape Town, SA
Some pics for better reference: