Earthing question for isolator board

I'm fitting an isolator board which will have piro's terminated into it (with earth concentric pots) which feeds submains upto flats. This is fed via a ryefield board etc.
I'm taking the concentic pots into the earth bar and the main earth coming in (35mm) onto the bolt which is directly onto the metal enclosure of the isolation board.
My question is, do I need to bond between the side enclosure (where the main earth is) and the earth bar or is using the metal casing which already links the bar and the casing adequate?
I'm thinking they should be linked but have been told overwise. Thanks

Put a link in. I dont know what metal the panels are made from, or where they are, but its good practice to link with a wire anyhow incase corrosion leads to high resistance in the future...

Yes corrosion, good point.
Should it be 35mm like the incoming earth or will a smaller earth be adequate?

I would link with the same csa.