That is good evidence of their mendacious behaviour. There does not appear to have ever been an entrance sign at this location. If there is one now, take a photo of it.
They will be required to provide evidence of an entrance sign at the location prior to the date of the alleged contravention. As can be seen in GSV, there was no sign in place in March 2023 and no sign ij place on the date you took your photos.
This one will be easy to challenge in a claim and it will be interesting to see whether BW Legal are prepared to let their client take this all the way to a hearing, where they will be in danger of a spanking and a cost order for unreasonable behaviour.
I can't believe how any reasonable person from the IAS dismissed the appeal in the first place!