This is a picture of the part that opens and what it should look l
ike opened its from a NE324 so don't know if it's the same as you have.
I remember finding hard to the open the first time
If your charger is mounted vertically there are 2 small clips at the top. Fiddly but push them down & cover will pop off.
Can you see the bit you push down ? It is that thin bit on the actual cover.
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