Sorry to say but you are, as you say, missing something because the road markings themselves are all that's needed and they are clear, as can be seen in the photos. Importantly, the spacing of the double kerb blips is absolutely correct, better than you see in most places i.e. within a car's length. This means that any driver paying the necessary attention could not miss them.
So, irrespective of any additional traffic signs the contravention occurred as regards the markings.
Presumably a commercial collection, which in my mind begs the question why customers in such restricted areas don't inform collectors of the hazards.
Are you the registered keeper with current DVLA details?
