Had an unpleasant experience recently, and wondered if anyone had any comments or similar incidents.
Went flying in conditions that didn't look perfect, but after consulting TAFs/METARs/ATIS and other pilots who had been flying, sounded like it should be OK. Immediately after T/O, decided viz had got a lot worse, and was going to return immediately to airfield. Flying low (1600ft), did all the usual lookouts ahead, behind etc. and started a gentle 180 deg. turn to the right.
Due to bad viz, not much horizon, so was checking my instruments more than I might usually do. Had completed about 120 deg. of the turn when my one of my passengers, behind me on the left, said 'plane to our left, very close'.
I looked to my left, and sure enough, at about my 8 o'clock, there was a plane, and it was VERY close

. By this time it was banking to the left, and all I could see was its belly.
My passenger said she had been looking in that direction, and called as soon as she saw the plane which, in her words, 'appeared out of the mist'. So it was very close by the time she saw it. Presumably the other plane didn't see me until that point either.
I was in front, and to the right of this plane, so I believe that means I had right of way.
Anyway, I've been thinking about this for a while, and I wouldn't even have been aware of this plane at all if my passenger hadn't seen it, which I find a bit scary!
I realise that unless you were in the plane with me you can't be sure how accurate my description is, but does anybody have any comments about things I should/could have done to avoid this, or is it just one of those things that you have to put down to experience?
And has anyone else experienced anything similar?