Did you get the back story to this fault?
Before it jammed was it hard to close? Was she having to slam it to get it to close? Was it opening easily? Did it spring open fiercely when she opened it.
There might be a clue here that will help get it open.
Like I said before, I've never heard of the latch seizing although I guess it's not impossible but I'd be looking else where first.
Is the solenoid still operating when you lift the handle? If so maybe try to use it somehow as it will be stronger than your fingers.
The only back story was that it hadn't opened since Christmas time. And no mention of slamming etc.
Anyway, there's been an update today, the door has been opened, the new latch assembly fitted, and all now working as it was before.
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