As this forum open its doors, I have the very dubious honour of asking for advice on a ticket which has just landed on my doorstep.
It is alleged that I "failed to drive in the direction indicated by the arrow on a blue sign/proceeding in the wrong direction

."
The story:
Driving down one road, traffic light. At the junction, there are 4 roads, the one I'm on veers to the left and under a railway bridge, or bifurcates to the right. I indicate to turn right, (as I have done for the last 16 yrs) and wait for the light to change. As I am waiting, I notice that there is a roadsign as above on the other side under the railway bridge, and say to my passenger (the esteemed Seminole): "Have they changed the directions on this road? Is this one-way now?" (yes, I know this is not the sign for one-way system), quick check for a no-turning-right signal, nothing to be seen, as the light changes, we proceed.
Now this.
Questions: This sign that means "turn left" according to the Highway code. Shouldn't there be an advance sign like this:

(Turn left ahead )
before the traffic light? Shouldn't there be a
at the light?
Have I just been magisterially screwed and will have to pay up, even though I am still not convinced that I in fact did anything wrong? Is there any point in appealing?
Thanks in advance if anyone can help.
Help much appreciated.