Bombard Tropik Valve Concern / Repair?

[Pav]

This valve is on the air deck. It is not leaking but you can see the surround for where the valve is secured has a crack on one side.
Would like to know if I can do anything to avoid this getting worse. Its been like it for a while and seems solid but I am in the process of checking boat over and want to preserve it.
Thank you for your help.

[Fenlander]

I'd just cut a round section of material the outer size of that smooth area with a hole to just slip over the valve then glue down with proper 2-part.