2 Gang to 1 gang dimmer switch wiring advice

I've been trawling about 25 threads for an answer to what I hope is a really simple question about how I replace a 2 gang switch, which currently controls two seperate hanging light fittings in my lounge, to a single dimmer switch.
I don't want to control the lights independently any more as they're only six feet apart in a small living room. but I'd like to brighten and dim both lights simultaneously with the one gang dimmer.

The current 2 gang switch has a single red, blue and yellow wires going into it and there is a bridging wire between the red wire port and another port.

I thought this would be really simple but I can get it to turn on one light or the other but not both at the same time. The dimmer switch has a L1, L2 and switching port. Or is a single dimmer switch simply not capable of controlling six bulbs (3 in each light fitting)?

Red into the "Switching port" (usually called common), blue and yellow together into L1. Leave L2 empty.

If it works with 6 bulbs depends on the rating of the switch and the total load (Add up the Watts of each bulb)

EUREKA!! Many thanks Mikeyd!

For future visitors to this thread, take care to match the dimmer to the load, not just wattage-wise but also the type of load. LED lamps cannot be dimmed by a standard dimmer and vice versa. If in doubt, contact the dimmer manufacturer for advice.

Doyle and Tratt have a great range of dimmers for most purposes and gave a fantastic technical dept.

https://www.varilight.co.uk/how-to-buy.php