thanks for all your replies, lads.
I have wired in grain of wheet 12 volt bulbs, as I am absolutely useless with electronics and after a visit to my local Maplins to chat about LED's I came away totally confused about the wiring in series and paralel , the resistors and capacitors that would have to be wired into maintain brightness in all "bulbs" and so opted for 12v lamps. I can just about wire those in on two circuits for interior and different running lights.
I have bought two very small 6v 1.4 amp hour sealed gell batteries ( for the sheer physical size of them) and mounted them in cradles just above and slightly aft of the gass tank but forward of the burner, and will be wiring up in series to get the 12v needed.
however as for a small dynamo, I literally have no room near to the two engines as the space between them aft is filled with an auxilliary fresh water tank, fed from a mechanical pump fitted to the port engine, and immediately affixed to the rear combing above the engines is a small oil gravity tank for the engines, so there is literally no room to swing even one of dear old Frank H's white metal cats!
However all your points about fixing a fan to draw in air is very much appreciated and I shall attatch one either side just aft of the lower stair case where there is a metal mesh grill suitable for an intake.
Hopefully I will keep you informed as to how it goes, and how cool my little batteries keep.
Again, many thanks for the input.
neil.
Just read the second part of your comment Bunkerbarge, and take your advice on using 6v rather than 12 v so will wire my batteries accordingly.I can then also use the same power source for the receiver. many thanks.