missing signage

Coupon-mad

I see why they didn't.

I wouldn't have looked at the sign if I had already seen the whole row of signs (knew I could park) and spotted the end of the bay was empty. I would not have looked again. Not with that lack of markings!

Altior

Well driving in central London and spotting an empty space with a lined box, next to double yellows and a bespoke sign tends to make one deeply paranoid, shall we say 😉

Yes it's poorly painted but there's more than enough clues that it's not a regular space. There's plausible and implausible, for me to infer that the sign was missed by accident is implausible. Plus I'm reasonably sure the sign was visible form the driver's door. It would be handy if the OP had a picture from the driver's perspective, ie from the right hand pavement, parallel to the space.

But, it's merely an opinion, I have no irrefutable evidence. I would be quite keen to see such a photo.