The problem with LED lights when sold as 240 Volts is that they have some form of step-down, like a transformer and choke circuitry (magnetics). It is the magnetics that the dimmers don't like.

Flourescents have chokes, energy saving bulbs still have magentics - albeit at a higher freqency and gawd knows what on the 240v side to chop (techie term) the 50Hz.

They had banks of LED lights in the ceilidh tent at Shrewsbury FF and they were bright. I bet it saved on the power cable size though. And the weight in the roof.