Firstly, thank you for taking the time to respond to me, and I am pleased that the decision has been taken to remove the sign.
However I'm afraid that I really can't see how the sign was used in an informatory manner. It is very clearly instructing cyclists to dismount and use the footway, and in no way suggesting that the alternative is to use the road. If that was indeed the intention of putting a notification up I don't think that it should be at all surprising to anyone that a sign reading "CYCLISTS DISMOUNT AND USE FOOTWAY" is being misunderstood.
Similarly, I fail to see why the road narrowing makes any difference whatsoever. I have not seen the road works narrow the bridge to single lane traffic, and even if it does during the works the cyclist should not simply be removed from the equation. Motorists are under no obligation to overtake cyclists at all costs. Rule 163 of the Highway Code advises that the overtaking maneouvre should only be undertaken when safe to do so. If the road is too narrow, motorists generally don't overtake - this is true on the road network in general.
Please forgive my fairly obvious emotion, but these signs seemed to be for no other purpose than to instruct cyclists to get off the road because more important traffic is coming through. This is the experience of many cyclists who are often treated only with passing thought or sometimes with outright hostility on the roads.
By instructing cyclists away from the road with no alternative route to reasonably use (indeed, the bridge still has posted notifications reminding cyclists of the fines applicable for cycling on footways) you ARE reinforcing the perspective that cyclists should not be on the road at all.
Thank you once again for taking action on this, however I do hope that in future thought will be given to all road users, and not simply create the illusion of safety by removing some of the most vulnerable.