18 Watt Lite Test Readings?

[JMPGuitars]

I've swapped in a 1k 3 watt resistor on the lamp and that is a lot brighter now, still not really bright but I don't want to go any lower and damage another one, so as far as I'm concerned that's sorted now.

Guessing and risk aren't required. Measure the new voltage level at the lamp. You'll probably find that it's much lower than needed to be safe. Trying a 470Ω would cut the voltage drop in roughly half of what it was without the 1kΩ resistor. If that's still scary, choose a value in between.