Can this cooker top be saved??

[AbandonShark]

Old-ish style iron type hobs, lots of burnt on old crud :(

I've tried normal household cleaning products, Astonish stuff and nothing gets off the worst bits. Is there anything else I can try? like an exorcism

A paste of warm water and bio washing powder. Maybe cover it with cling film so it doesn't dry out too quickly. The enzymes should soften the muck.

for the cast-iron rings, you can use a brillo pad.

For the enamel, use a green nylon pan scourer with WUL or kitchen cleaner. A nylon brush is more gentle.

If you rub the cast iron with half a drop of cooking oil on kitchen roll, once they are clean, they will gleam.

Brilliant! Thanks everyone, I will try all of those. The burnt on bits have just been baked on so many times that they really don't want to shift. I won't let them beat me!