DIY Doctor UK DIY Forums

Been slightly leaking for years, dribbled over the light fitting which had an integrated fan. All rusted through so I removed the light/fan and the cowling to find this plastic plate (Picture Supplied).
I can't get this to come off, have removed the bolts that I assume were holding it up.
The long bolt in the middle just spins, and doesn't move the cone fitting on the roof of the conservatory on the outside so doesn't seem to be connected.
My idea was to remove the plastic plate and seal the ceiling with silicone and reassemble everything with a new light.
Anyone familiar with this or any ideas on sealing it please?

It's probable that the mounting bolts have back-nuts which have rusted up and are now just turning with the bolt. If there's no other obvious mounting bolts, the chances are you might just have to resign to brute force and repair the damage after you get it off.

I was considering the brute force and patch up method but didn't want to do that until I had at least a 2nd opinion.
Thanks for getting back, I will let you know how it turns out.