I had a similar experience of "assumptions made" not relating to the true facts last year. I fly from Barton where we have two runways in use 27L and 27R both with RH circuits with the reciprocals on left hand circuits. Landing info is normally in the form "Runway in use 27 Right with a Right hand circuit"
I flew into an airfield where I have not been before and was told "Runway 27 Right"
and simply assumed that there were two runways with the 27 designation, which seemed to be confirmed by someone else who almost immediately called "final onto grass" which I then assumed would be the 27L as opposed to my 27R as I did know that the airfield had a tarmac runway. Consequently I planned and executing a left hand circuit onto what i thought was 27R.
I was now established in the circuit and downwind with nobody else around other than the ground controller on duty talking to some other aircraft who were traversing the overhead. I duly made all my calls and executed a standard no drama landing. It was only when I then both heard and saw the next arrival executing a right hand circuit
as opposed to my left hand
circuit that I realised my mistake. I immediately apologised on the radio but said that at no time had I been told "27 Right hand Circuit" - hence the assumption and confusion. The controller's response was: "you aren't the first and you won't be the last to do that". That was not really of any consolation though!
The confusion could have had dreadful consequences if the circuit had been busy, so from now on I will actually confirm or ask for confirmation of circuit direction regardless. I still hold that the landing information given wasn't in the correct format but as they say it's no good being in the right if you are the one who gets injured. Moral correctness isn't worth diddly squat in hospital or in the morgue