Vapor barrier foil on radiation protection plate at wall penetration

Hello everyone,

we are currently retrofitting a wood stove into our prefabricated house.
Our chimney installer has installed a wall penetration for the flue pipe into an exterior wall (timber frame wall).
Our wall structure is such that on the inside of the wall, after the 12.5mm drywall panel, there is a 16mm wood-based panel (OSB).
And between them, a vapor barrier foil is installed.

Now our chimney sweep says that in front of the wall penetration there should be a 100x100 cm radiation protection board (20mm thickness).
This would then replace the drywall panel and the wood-based panel at that spot.
Can I then simply apply the vapor barrier foil onto the radiation protection board (instead of on the original OSB panel)?
And then a (thinner) drywall panel on top so that the wall surface is level again?
Or is the vapor barrier foil not allowed to extend up to the flue pipe anyway due to fire hazard?
Maybe the vapor barrier foil is not necessary anymore because of the radiation protection board, since the wall at this point is then already tight enough anyway.

Many thanks & best regards
Michael