Shimano M431 Alivio Crank Removal

I am new to this world of cycling and would like to learn how to maintain and repair my Voodoo Bizango rather than spending a small fortune on visits to Halfords and the LBS both of which I have been unhappy with the level of service on separate occasions.
I have noticed that I am getting a creak from around the bottom bracket when pedalling and it seems more noticeable when going up hill. Having had a look at the spec sheet for the Voodoo I have an octalink bottom brace and Shimano M431 Alivio Crank Set. Now I have tried removing the bolt from the crank arm with an 8mm hex key but it is bloody stiff, I tried to loosen anti clockwise, is this correct? maybe I need more leverage so I plan to pick up some scrap steel tube/bar from work tomorrow.
I just wanted to know whether there was any special tool required to remove the hex bolts as they have a small hole in the head? As shown in the two pictures below. I have read the Park Tool Removal Manual and didn't see any 'special' tool required to remove the crank bolts.
image by sunday-trucker, on Flickr
Any of the Bizango owners got the cranks and BB out and done a home service? anything I should be aware of?
Thanks for any assistance provided
I have noticed that I am getting a creak from around the bottom bracket when pedalling and it seems more noticeable when going up hill. Having had a look at the spec sheet for the Voodoo I have an octalink bottom brace and Shimano M431 Alivio Crank Set. Now I have tried removing the bolt from the crank arm with an 8mm hex key but it is bloody stiff, I tried to loosen anti clockwise, is this correct? maybe I need more leverage so I plan to pick up some scrap steel tube/bar from work tomorrow.
I just wanted to know whether there was any special tool required to remove the hex bolts as they have a small hole in the head? As shown in the two pictures below. I have read the Park Tool Removal Manual and didn't see any 'special' tool required to remove the crank bolts.

Any of the Bizango owners got the cranks and BB out and done a home service? anything I should be aware of?
Thanks for any assistance provided
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Once you got hat bolt out you will need a crank extractor to get the crank off
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When I've had issues I thought were BB it has been the above.
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pretty certain it isn't any of the above, they are easy enough to check so will give them all a once over to be sure, Although I have recently swapped seat post and it was making the noise before hand. I have read of noise that sounds like it comes from the BB coming from somewhere completely different, god knows.
I used a 1/2 inch to 3/8 inch wrench reducer with a socket 8mm allen key and LOTS of brute force (well, lots for me anyway!) and the bolts came out in the end. Crank removal was actually simpler, but it did help that I had the right tool in the first place. BB removal comes tomorrow when the parktool tool arrives!
2011 Specialized Hardrock Sport Disc (son #3s)
2013 Decathlon Triban 3 (red) (mine)
2019 Hoy Bonaly 26" Disc (son #2s)
2018 Voodoo Bizango (mine)
2018 Voodoo Maji (wife's)
P.S. If you plan to work on you're own bike I strongly suggested buying a proper tool kit. It's a bit on an outlay but it's soooo much cheaper in the long run.
Thanks. Yeah I am a scrawny weakling so everything feels bleeding' tight, need to man up and get some leverage on it.
I have a few things already but plan on buying proper tools as required, what male doesn't enjoy buying new tools?!