Dual RCD boards can facilitate this compliance,
They do not comply with reg 413.
I advised the correct option.
I haven't the foggiest why you've mentioned 413
If it's a case of opinion, I would say that the opinion of the IET (who publish the Regs, OSG, GNs etc.) and the consumer unit manufactures would be correct and you would be incorrect.
IET have even put a nice full colour illustration of a dual RCD board on page 25 of the On Site Guide.
