UK Second empty meter cabinet for a consumer unit to feed several garden circuits. Can a standard metal csu be fitt

[sidekick]

I have a customer who has installed a second empty meter cabinet for a consumer unit to feed several garden circuits. Can a standard metal csu be fitted in here, does it have to be in an ip65 enclosure also or can a ip65 plastic csu be used.
I get csu has to be non combustible within a dwelling, is a meter cabinet within a dwelling?

 

[Strima]

It is within the boundary of the dwelling so would need to be compliant.

What are the risks of water/moisture/debris ingress within the new meter cabinet? Bear in mind that suppliers often fit isolators in there.

 

[sidekick]

It is within the boundary of the dwelling so would need to be compliant.

What are the risks of water/moisture/debris ingress within the new meter cabinet? Bear in mind that suppliers often fit isolators in there.

Figured that so thinking metal but then whether ip65 needed or not. It is a brand new meter cabinet next to suppliers cabinet so independent from any thing they need in the other one with cut out. Just not sure on ip rating needed of csu if inside a meter cabinet . looks ok but of course no idea of cabinet spec re ip rating