That will be the day.
I think we will know that bit paper means nothing, except we can actually get paid decent money for our exports. What it doesn't actually mean is it's been installed properly, or works properly. In fact I'm baffled* why they insist on it, they don't even ask for proof that the electrical installation has been signed off.
*When you add up all the systems that don't have MCS, because it's not a legal requirement, so solar can legitimately be installed without it, there must be an awful lot exported that's either not paid for at all, or they get peanuts for it, someone somewhere is profiting big time.
Unfortunately MCS is something that has managed to hang on after the FITS systems.