Having been in this particular branch of the job for some years myself, I suggest you do NOT listen to the ex-mil pilot saying that an IR isn't essential. He is wrong (I'm ex-mil too). In UK the aircraft will often fly in very poor weather conditions. If it doesn't, it isn't a viable / reliable method of transport.
Imagine the situation - "Sorry Boss, we have to turn back - I'm not allowed to fly in that cloud so there is no way over those hills.."
I think that would very quickly turn sour (I've seen it happen, btw).
Or, even worse - "Well I'm not qualified to do this and I know it's dark, but it's probably only a little cloud - here we go...."
That's happened too, I could give two examples of fatal accidents to emphasise the point.