I see, it is strange the tolerance differences between different batteries. I won't force it, just try firmly to shut it. Currently have the batteries in my RX2/3 though and thats working so don't need to try right now.Don't be forcing anything, my VTRS VBoy jams up with certain batteries but works a charm with Sony VTC5A's. Even VTC5D's get stuck.
This is the mod, and this is the battery compartment. You can see the little clip that clips into place on the part that opens, and also the lip where it clips into on the mod in the second photo.Not seen that mod does it have spring loaded battery contacts inside that might have seized?
Just floating it as an idea.
Thats a good price, I highly rated the Yihi boards when I was collecting mods. I believe the SX350J was the high end model at the time, yours uses a 500 which I imagine is more advanced so £22 is a bargain.
Oooh, now I want one! At least I can kind of justify it where so many of my mods are not working now lol