You are correct, no prior warning signs exist in Palace Road. Anglesea Road has none neither.
This is an experimental scheme and you need to request the Traffic Management Order to see the details and conditions.
In my opinion, as this stands the signage is not fit for purpose. The signage that exists is not even illuminated after dark so i am sure nothing is being enforced when it is dark.
I walked around there today and in 40 mins I counted about 15 vehicles in each direction. Incidentally I did not see a single cyclist. Clearly the experiment isn't working as this section of 80 yards of road is supposed the be part of the Tolworth cycle route. I haven't a clue where the cycle route is suppose to go after it leaves this section. Then next section includes a 1 in 5 hill.
Regarding the except access. There is a car park at the rear of the school for about 20 cars. Also some private dwellings, a electrical sub station and a proposed development site. I can only assume that Access refers to accessing these places. How the camera knows who is accessing and where.... Perhaps an experimental camera!
I suggest you find some help to make an appeal.