Hi Arch You seem to have the DIY 3 plate quandry.
If your luck is in you need to check the wiring you have at the rose.
You should have 3 twin and earth pvc sheated (or god forbid rubber) cables each with a red black and bare copper earth wire.
IF this is the case check if the tisted reds and twisted blacks go to the same cable . If this is so the spare red and black wires should go to the third cable.
Only if this is the case AND all other lights on the same circuit are working , can you try the following.
First turn of the power connect the 2 twised blacks to the 2pin BLUE connector of the rose. Connect the 2 red twisted wires and the single red wire together in the centre 3 pin connector. Finally connect the single black wire to the BROWN 2 pin connector. Make sure the dropper flex is connected Brown to brown --Blue to blue. Put power back on and test.
With this method the worst that can happen is that another light in the house will come on dimmly when you turn on this light.
Any probs. repost
HTH
CJ