Hi,
Yes, its an A1024 label, with a report of a fault with either the pole or the wires, normally for wires being lower than the minimum height across a road, or more than 3 wires going in the same direction, or faulty climbing steps.
If the pole was dangerous to climb for reasons such as it was rotting at the base, or there were spikes on a gate underneath it, there would be a red "D" nailed to it. The yellow label means that the person that spotted the problem has called the control desk and reported it, and they would have been given a reference number that they should have written on the label, so the next engineer knows of the fault and won't report it again. The faults are prioritised, so if its urgent it will get seen to rapidly, if not urgent, then will be left until a remedial party have some spare time.
The white label you saw, was probably a yellow label that had been there for years and faded with time.
alf.