Just returned to chess after 40 years (yes I know). I have a memory of being taught that the kings could not face each other on the same line or column. Chess Titans computer game doesn't seem to recognise this or have I got it wrong. I understand the rule of Kings not being next to each other but I'm talking about the along a whole column for example
The reason your game doesn't honor this rule is because it is not a rule.
There is some confusion over "facing each other" If you mean two Kings directly facing each other (where one could theoretically attack the other) then yes, it is an illegal move because one cannot move their King to where it can be attacked; however, if you are talking about "facing across the entire board" in a manner where if a King was a Rook it would be able to attack, then perhaps you have confused chess with one of the older games attributed to it's lineage.
Chinese chess has this rule, and it is part of the common strategy within that game to limit the opposing King's position by placement of your King. In Chinese Chess, however, the kings cannot leave the palace and the if the opposition is blocked by a piece the other King has more leeway in movement.
Kings cannot legally be on adjacent squares, but otherwise opposition (being one square away from the other king on a rank or file, or even diagonally) is one of the most important principles in the endgame, since the king taking the opposition can force the other king to give way, gaining space. Being any odd number of squares away from the opposing king with the move in any of these configurations is having the distant opposition, which is just as significant as close opposition.