"I couldn't work out which way to look, had to think about it each time, and then just thought sod it and looked both ways each time."
If you only know one way to do something then it is a no-brainer. Once you know two ways then you get into a state of metastability while you make the decision.
One dark night in the UK I was in the right-hand lane of a one way system. Coming to a halt at a T junction to join a deserted dual carriage way - I was suddenly confused about which side of the central reservation to turn on to. My year in Sweden driving on the right had obviously conditioned me to that "I am currently on the right" check when making such decisions.
In Sweden they still had the precautionary markings from when they converted their roads to the right. A nice curved white line traced your route onto the correct side of the dual carriageway.
The Stockholm elevated through roads had presented more of a logistics problem post-conversion. You entered from a (previously an exit) slip road into the traffic in the "fast" lane. To leave you also had to manoeuvre into the "fast" lane first - and hit the (previously an entry) slip road at that speed.