I thought I'd covered all bases, studied the tutorial videos & took my time but........................its all gone horribly wrong

What have I done wrong ?

Thanks,  Mick

I agree this error.

And with my own experience, i can advice you to apply 2 coats of tooling Gel coat, as the first one looks too thin in the angles

You final part looks like there is not enough resin? or maybe some leaks?

Regards,

Seb.