Sound like you have a 3 core & earth cable with a strap across the switch.
The red will be your live into the switch & the blue & yellow will go back to each one of the lights.
Place the red into one of the third hole’s with a short length of red cable to the other third hole. (This will be the C on your other switch)
Now place the yellow in L1 of one switch & the blue in the L1 of the other switch. The two L2’s will be empty. Naturally make sure all is off at the fuse board & all your terminations have no copper wire showing.
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