Is this normal? Please help!

[Howhardcoulditbe]

First post so please be gentle

I’ve recently bought a house and wanting to use the garage as a workshop / gym.

The roofing membrane looks pretty nasty from the inside and there’s a few holes, plus it’s rotten away by a few inches at the gutters. I therefore want to replace it (myself) with a new breathable membrane (Klober Permo Air).

Few questions:

1. Should there be more overhang than this?

2. Is it normal that the battens end before they get to the gable wall, rather than resting on top of it?

3. Is it normal that the top of the battens are almost flush with the top of the wall?

4. Is it normal that the existing membrane stops before the gable wall rather than going under the tiled undercloak (if that’s what those dark tiles on the bricks are called)?

5. When I replace the felt, could I run the new membrane on top of the tiled undercloak and below the mortar that I’d use to bed the verge tiles? Or would it be better for me to just replace end the membrane where it ends now?

Thanks for your help!