Here in the UK all G Reg A/C have the fire extinguisher mounted below the CB panel which should be in reach of the pilot. This I believe is/was a CAA requirement.
Below the pilot perhaps? who sits on the right hand side. In most 44's I've have ever seen or flown this is the case (easy to kick it getting in too).
The UK CAA like to have the fuel cut off value selected to 'off' for landings when on fire - so the landing has to be autorotative and fast for max RoD for much of the descent.
If the M BATT switch is off (and ALT) then the electrics are off so any blue smoke should clear by venting the cabin.
Main thing, get it on the ground ASAP and keep the cabin clear on smoke (if M BATT = 'off' then no instruments for flying in smokey IMC)
I'm not sure Mike JH Smith's in-flight fire is in the same category - this was a neglegent discharge of a flare not an electrical fire (more white smoke..)