Yeah, I guess so.
I'd not be fussed if I didn't have my daughter with me who has an early start on Saturday so I want to get her home to bed as quickly as possible.
I've used Just Park a couple of times, although not for that area, and it's always worked out fine.
(This is no guarantee, do your own research etc etc!)
Stratford Multi-Storey might be better (or is an alternative at least): https://www.newham.gov.uk/Pages/Services/Car-parks-and-on-street-pay-and-display.aspx
For complicated reasons I'm driving. Appreciate it will be a ballache getting there, but that will be offset in an easy journey home.
I'm going to park at Westfield or, at least, aim there initially and take a Plan B if required.