Something rectangle that sits in the top 1/3rd of the vents would be cool, like a P3 gauge but with more specialised info available. Having DCCD there would be cool 

f*** it just get one from Pickapart, they're like $40.

Likely the alternator has a replaceable rectifier unit inside. some can even be disassembled and individual diodes replaced.    

Battery tests fine, no resistance between battery posts when its disconnected from the car i only get resistance of 15ohms when i disconnect the +ve lead and test between +ve lead (not battery post) and negative  lead but yeah i realise thats f***ed haha, thats why as soon as i tested it i was like arrrrrrrr that not good    Yeah i might just order a new alternator to rule it out - heres hoping i can find one haha 

Something is f***ed here, if you put a car battery across a 1 ohm load you get a good spark and a lot of heat very quickly. Unless everything involved is rather large.   Suspect something is kooked with your alternator.