They are in the second lane, then they are too close to the left most lane. A vehicle (especially a large vehicle) passing up the inside could be very close. If the yellow rider were to move slightly to the left, the blue one would probably swerve towards the left lane, but there's no where to go.

They are also encouraging in-lane overtaking, which might just about work for a motorbike or another bike, but anything wider would be a problem

The yellow topped one is probably OK in lane position if the other cyclists weren't there (but why not another metre to the right). However he's very close to the blue one. The blue and stripy ones run the risk of being hemmed in by traffic from the rear

Thanks for the reply! Studying the photo more, I see that you are right about them being in the left of the second traffic lane - it's not parked cars like I thought previously.