The above is one of many reasons why a lot of electricians insist upon supplying materials - or at the very least writing a comprehensive list.
Your new board is not what many would recommend, for reasons previously outlined, but having a dual RCD board doens't present any inherent danger. It can be argued that such boards should no longer be fitted, and I'd be the first to argue that very point, but changing it again will present significant cost and this would be borne by you as the board was your choice.
Provided the wiring in your home is good, and connections sound, the risk of problems should be exceptionally low and it might be best to get any real issues resolved and chalk the rest up to experience. I doubt you'll be using this electrician again, but in future would look for word of mouth recommendations or ask for someone local on a specialist forum like this one.