Why didn't you pay the PCN on the 4th of April when you saw that it had been reverted to £65? That reversion implies to me that Newham reissued the Notice of Rejection with the discount reinstated, probably for a further 14 days? Either they did so because the Adjudicator directed that the NoR be re-served, or they pre-empted that possibility and re-served anyway. Or they have a standing instruction to do so still in place.
I would have thought that £65 is the best outcome you were were ever likely to get. There doesn't seem to be any chance of prevailing at adjudication on the merits of the contravention itself. Basically you're bang to rights.
A procedural mess up by the Council might still win at adjudication but we won't be able to tease out that possibility until you get the case in front of the Adjudicator and the full evidence pack with the case progression history is served on you.
At the moment all you can do is follow up with the London Tribunals and find out what was directed, if anything at all, as advised above by cp9759. Please report back when you do so.
You may well have to wait for another Order for Recovery to be issued and submit a new Statutory Declaration.