I think BYPA had a single AC inverter and would be unable to fly SPIFR. Public transport flights at night (post Matthew Harding) require an equivalent of IFR, therefore the trip in question would have been Private. (Correct me if this is wrong please.)
Are Private flight visibility limits 800m for night VFR operations? I know there has been talk about changing the PPL VFR limit to 1,500m and even 3,000m. Reducing airspeed helps with lowered vis, so in a way the harder one to deal with is a low cloud base. All very sad...