If you're converting to LED from halogen you can very often just change the module for a v-pro dimmer which does all the dimming types and programmable low and high settings. They are good value if you buy them from screwfix as a pair in white and strip them out.
you might need a different dimmer switch for halogen vs led (leading edge vs trailing edge)
https://www.wholesaleledlights.co.uk/trailing-edge-dimming-for-led-bulbs