Which side of the sign can I park?

This road sign means that you cannot park or wait on the side of the road where the sign is, on the sides of the sign pointed to by the arrow:

It is usually placed at the side of the road so that the sign is parallel to the road with the arrow pointing left in the direction of the traffic.  With both arrows you cannot park on either side of it.

Somewhere there is usually another one with a single arrow to mark the end of the restriction, and you often see this sign in turning circles on housing estates.

If the measure is only temporary, then it has a sign below with the effective dates:

So I was quite confused the other day when I wanted to park in this road:

The signs are not pointing up or down the road, but across it!  But even if they were standing so that the arrows pointed along rather than across the road, something else is still wrong.

The sign in the background only has one arrow, and it does not point to the one in the foreground.  So whilst the first sign tells me not to park on the right of it, the second one tells me that it is OK on that side, but not on its right!

In fact there was a third one in this chain that was just the same.  I’m sure that the local residents didn’t have a clue which side they were meant to be parking on.  A number of the cars that were parked between the signs had apparently been there when the signs were put up, but I’m told that this was not a problem as it turned out that the secondary signs had been left off – and the parking restriction was not due to start for another three days!

But still, when confronted with a situation like this, what’s the best thing to do?