Two clear "No Right Turn" signs that you seem to have ignored.
We've had a recent thread on this location for the exact same thing; driver wanted to turn right at the traffic lights but its NRT there so then turned right after the crossroads. GSV shows the signs have been there for many years now.
I'm not sure how the thread turned out, but you can search the London Tribunals statutory register using the location as your search argument with a date range, (try the last two years). However, I can't see a win here, I'm afraid. There may be a 'technical' argument based on Greenwich mismanagement of the enforcement process, so wait a bit, but don't miss any deadlines on the PCN.
