I had a look for that book. £48.45 on Amazon! It wants to be good for that price. Ill add it to my x-mas list

The LEDs im looking at are 15 degrees i guess that puts them towards the dimmer end.

So, using LEDs on 12V in parallel is definately out of the question. Looks like ill be using a series-parallel type circuit. That way each of the 4 sets of LEDs should only use 200mA of current.

If i only need 200mA now is it still better to use a mosfet instead of an NPN transistor? Yes i can use NPN now with these other LEDs