It would be interesting work through the legal issues as well, just to get a better picture of how this might apply if the spaces were charged for.
The law is very specific noting subsection 1.9 of the Roads Scotland Act 1984
..(9)Subject to subsection (10) below, every road which is entered in the list of public roads kept by a local roads authority shall vest in the authority for the purposes of their functions as roads authority: but such vesting shall not confer on an authority any heritable right in relation to a road.
Roughly translated - the roads authority (Council) is not entitled to make money or gain benefits from the use of the land on which the road (which they own) sits, and this is why the money earned from parking charges (in theory at least) should only be used to cover the costs of managing the road & parking on it. Any 'profit' would be due for payment to the owner(s) of the land - generally the frontagers, to whom the land should revert if it is no longer required for use as a road (ie for the sole statutory purpose of moving traffic on foot or awheel). Now here might be a fine challenge for those wanting a bigger front garden. Several examples of this exist in Glasgow, with the university, and SMG taking over entire streets which no longer connect 2 different places, as they own all the property on the street.
If the road over your land (title plan) is stopped up as a road it comes back to you - so you could rent it out as a parking space, and take the income, or convert it to a pleasant green space, or somewhere to park your bike.
It might also link to placing cycle parking units on the road and also charging for the use of cycle parking units on land belonging to the flat-owners (an irony there on being charged to park on land that you own?). It might also prompt a bit of legal fun if you can prove a piece of road on your land is not required for passing & repassing of traffic (because 95% of the time it has a car parked on it) if it is used for parking, then obviously it is not required for use as a road, and under Section 79 (I think?) a move to de-list that bit of road and revert it to your ownership might be promoted. Anyone up for setting a precedent?