Night flights in the UK must in flown in accordance with IFR, for good reason.
If I read this correctly, it has nothing to do with being flown IFR at all. It has to do with a city council planning people allowing them to land at night.
As for having to fly all night flights under IFR---I disagree with that too.... Lets fly IMC under IFR, but I see nothing wrong with flying VFR night flights....I have many hours at night and never encountered IMC, yet have come close to going inadvertent IMC during daylight. The accident rate of EMS flights in the US is not limited to night time.