You have yet to post the PCN. Please do not redact PCN Number and car reg, because we use these to view the online video.
GSV is way out-of-date, (August 2020), so we need to know if there is an advance warning sign for a left turn approach. If there isn't you look to have a fairly strong case, but only at London Tribunals because Greenwich, (wanting your money !!), will just refuse any reps you submit to them.
The photos you have posted show the single sign would be side-on to a left turn approach. Don't think for a moment that the council have any brains or intelligence; they haven't but are very good at stonewalling and sending out Fob-Off letters. Going to London Tribunals means you have to risk the full PCN penalty. Nothing to pay if you win, of course, and the full penalty if you lose, but that is all, there are no additional costs. And Greenwich may fold and concede just before the adjudication hearing. It's a favourite trick of London councils.
Were you using satnav to drive there ?
Main point we need is the signage - is there an advance warning sign