Council photos:
(https://i.imgur.com/LxLREog.jpeg)
(https://i.imgur.com/74391Jt.jpeg)
(https://i.imgur.com/3pr9VR7.jpeg)
(https://i.imgur.com/RiMCCmY.jpeg)
(https://i.imgur.com/cQmu41O.jpeg)
(https://i.imgur.com/3V9ovII.jpeg)
While I don't disagree with HCA on the fact that there does appear to be a contravention, I also think the signage could be clearer and it is worth point this out, so here's my suggestion:
Dear London Borough of Redbridge,
I would like to ask that this penalty be cancelled as I was the victim of an honest misunderstanding of the signs. The signage at this location permits footway parking at certain times and indicates a waiting restriction at other times, and as a blue badge holder I am exempt from the waiting restrictions I was labouring under the misapprehension that I could park as I could have done outside of the restricted times, i.e. with two wheels on the footpath.
While I now understand that this is not the case and I should have parked fully on the carriageway during the restricted hours, I would ask that the council exercise its discretion to cancel the penalty on this occasion.
Yours faithfully,
Send this via the council website and keep a screenshot of the confirmation page. In the meantime I'll get hold of the footway parking resolution.