It's looking like there is a fault on the loom.
There's a dead short on the +ve and -ve (battery terminals) when the ignition is switched on.
I checked the main fuse that had blown and it was a 30A which seems a bit high to me.
I'm thinking there's been a bit of melting plastic going on in the loom and 2 cores have become in contact with each other.
Until I get some more time to sort it I'll be riding my lads moped
27mph!!! It's getting de-restricted as soon as possible too!!!