Although FAA rules permit otherwise, you are not VMC/VFR over the water at night even when you are completely clear of cloud.
Is that because other jurisdictions, i.e. UK and Ireland, require all night flight to be IFR, or is that just an over water rule.
There is legal night VFR in Canada and US, I think France and Portugal, too.
I've done a lot of night VFR. It's really IFR, or you're best to treat it that way. In remote areas, i.e. ocean, you can't really see things below an overcast, or sometimes not much even with a clear moonless sky. Full moon, yes, you can land at a strip with a full moon and no lights.
So you say that this was 100% an IFR flight because it was night?
200 feet doesn't seem right.