Emma... if i had £1 for every phone I received when I was the Approach Control Supervisor at Heathrow from people making similar claims I'd be a rich man.
It's nigh on impossible for a human to distinguish the vertical distance between aircraft in flight. The different sizes of aircraft involved, the weather conditions, direction of flight, viewing angle, etc., all make it very difficult, if not impossible to determine an "airprox". Maybe two jets were heading in the same direction..... but what is a "sharp" turn??
Forget it..