Indeed it used to be private, because GSV March 2021, (the latest view), shows the private parking signs : -
https://maps.app.goo.gl/gFyK1zW3jkAjkPDi8Clearly now subject to council enforcement, but they seem to have been totally dozy when signing it. The double-yellow lines between your bay and the next are your Get-Out-Of-Jail-Free card, as the bay is now separated from the next one, so needs a sign, and as SFM says, there is a pole there for a sign, but no sign on it.
However, such is the venality and rapacity of councils nowadays, they will refuse any informal challenge, and probably reps to a Notice to Owner as well. So you must be prepared to stand your ground, and take them to London Tribunals.
I see that when it was private, the small kerb square with a tree that is separating the two bays had no yellow lines; Newham have added them.