Belt slapping wildly - belt tensioned - pics added

[Niall]

Strange way of doing it, i always pull up tight on the crank, around the pump, keeping it tight, up over the cam, and then push inbehind tensioner, at which point everything should be pretty tight. but providing after running it the lock points still line up bang on, timing isnt the problem

As i said, i havent even seen a XUD belt pattern but that kind of made sense in my head lol.

Other than that, im out of ideas. Maybe it just doesnt like you because your miserable and ginger?