To comply with this: https://www.legislation.gov.uk/uksi/2020/312/made
the electrical installation must comply with the 18th edition of BS7671.
That consumer unit does not, as it has no RCDs for most of the circuits.
The existing CU is obsolete and will need to be replaced with one containing individual RCBOs for each circuit.
It doesn't need 2 RCDs, and no one should even be suggesting installing such a thing.
Not sure I agree with this.
The legislation says it must be inspected to the 18th edition - and as we all know EICR's allow C3's for these stuations.
What does your EICR actually list as the C1's , C2's and C3's?
As for 2 RCD's - they are still sold so there's nothing stopping these being installed but who does? Only a cheap skate