Dave is that voltage measured under load or by the open-circuited secondary winding?.
2V is a fair bit to "drop" in a case like this and I don't personally think a resistor would be suitable for this sort of application.
Any power "lost" would be dissipated as heat.
I'm assuming you are using fittings with the small Halogen burner lamps in them, if they are 12V lamps, should it make any difference?.
I was under the impression that these lamps have a reasonably short life anyway.