Conusmer Units (CU) are type approved to be used with the the manufacturer MCB’s, RCD’s for thermal dynamics etc. However, as long as the non brand breaker (MCB) fits the CU properly as the original ones and there is no signs of thermal damage to it or adjacent breakers, then at the very most on an EICR (inspection report), it would be given a code C3 rating “is not compliant with CU manufacturer, but is not immediately dangerous ether (or likely to be if its been fitted a few years)!
You see this alot especially with older boards, where perhaps the manufacturer doesn’t make or has updated the breaker so it no longer fits, but one from another manufacturer does so therefore it is used. The general consensus is, if it fits right and theres no inherent problems its fine and coding as above. If however its doesn’t fit like glove as the original, its another matter. I will see more when you put a pic up.
Before moving on with the rest, does you EV charger also have its own consumer unit and is the RCD/RCBO type A (Pic tomorrow if not)