When I was conducting tests for the DVSA, I queried the road markings on some roundabouts. I was told that a lot of roundabouts were having to remove right turn road markings on approach to stop people attempting to go round the wrong way…
I was sceptical about this until I found myself having to stop candidates from doing just that on several occasions 
I conclude that they are altering markings to accommodate the falling standards of new drivers.