Thank you so much jon@work and martysmartie for the replies. So shall i use the second diagram now not the first one i posted, Just out of curiosity if the second one is the better one, why is it better?

Also the fan switch on the second diagram only has a single wire going to it, and then the fan switch is earthed, how does the realy know when to switch the fans on when the wire from the relay feeds power to the switch.

Many thanks once again