Re-sealing headlights

I had dirty headlights due to water ingress so I split them in the oven then cleaned them.  I cleaned off the old sealant and now I'm looking for a product to re-seal the them.  Other people have used the original stuff but like I said it took mine off.

looking for info about stuff people have used that I can get in the uk.

I've bought some pro seal rtv silicone gasket adhesive.  Said its for headlights and withstands water and high temp.

Sounds a sensible choice, never done that so wouldn't have a clue what to use.