Are you inside London or outside?
I presume there are no signs up allowing parking on the pavement?
In that case, that is a problem I'm afraid.
In London there is an automatic presumption that parking on pavements is disallowed unless there are signs at the location allowing it.
The fact that they have previously allowed it is no defence per se.
I'm very sorry but that is the reality. You don't acquire a right to parking on public land by prescription I'm afraid.
Can I clarify anything for you?
There is a contravention in that although they don't often rely on it.
Yes, they can do that.
They do not often rely on that contravention but they could if they wished to.