I've been using these connectors from Maplin for connecting some of the electrics in the engine bay, they are rated at 5a. Any idea if i can get some that have a higher rating for headlights etc.
Rescued attachment connectors.jpg

ooh, i quite like them!

Try the Farnell or RS components websites.
You will probably find too much choice.
I bought some parts from Farnell recently.
I think the minimum order for card payment was £20.

5 A = 60 W shold be enough for a single head lamp

double or triple up the contacts?

Yup- that's what I'd do. Just use two contacts

Of couse you could always use the E-type connectors, they had something rather similar!! Quite big + heavy thought!!!