If sufficient visual references are available to determine aircraft attitude and position then night VFR is perfectly OK, subject to suitable training and qualification(and always has been, despite the previously obtuse wording of the UK rules, now very recently changed to allow night VFR per se).
However, without those visual references, it's an IMC flight, there are no two ways about it. Flying in any hilly area such as the Lake District is a potentially lethal place to find oneself in inadvertent IMC, especially on a windy, gusty night, as appears to have been the case here.
But deliberately putting oneself in a position where one has no training or qualifications for night flying, let alone for IMC flight, then taking off where the former is a certainty and the latter quite likely, is naivety at best and more like gross stupidity.
Also taking into account the appalling disregard of proper and legal standards of airworthiness and maintenance, regrettably this accident appears not to have been a case of "if", but "when".
I hate accidents like these because it makes Joe Public regard all helicopters as dangerous things. It's actually what some people do with them, or try to do with them, that's dangerous.
