Just to ask the obvious.....why not just install the AFDD?

If the concern is nuisance tripping of the RCD element in a combined protective device, you can install a standalone AFDD module in a mini din-rail enclosure adjacent to the DB. Then the CPD on the DB can be an MCB with an accompanying risk assessment for the omission of RCD protection on that circuit.

There is also a concern that the AFDD is susceptible to nuisance tripping but I'm not sure on the statistics of AFDD performance.

I'm not sure you can buy an AFDD that does not include the RCD function, certainly not easily from most makers.

there may be a very limited no of ways to have AFDD without an RCD.

What Complimentary Network Services are so vital that they have to say on if the building is no fire - and is a UPS or redundant suppplies an option ?

Mike.

Hager and Proteus both have them.

Hager and Proteus both have them.