Sp3000 remove lens filter

[Sunny35mm]

Hello, 

Trying to remove the lens filter below the lens on SP3k. I see the slits right above it for a spanner wrench and have tried this but it didn't budge at all. I do also see some holes in the lens filter outside that could maybe for spanner wrench with pointed tips. Can anyone let me know the proper way to remove it? Ours has some haze/dust on the top side of filter and it looks like one of the lens screws is about to fall off so trying to sort it out.

Attached pic for reference.

 

Thanks