Thinking about it, for some reason these fancy type fittings tend to contain torroidal wire wound transformers, instead of the electronic type trannies.
You can not dim wire wound trannies with a standard dimmer. You need an inductive dimmer for this to work.
I have found an IQ intelligent dimmer switch in the same style as yours.
This is suitable for use with both electonic and wirewound trannies, as well as all standard lighting loads. (It's not cheap though)
http://www.tlc-direct.co.uk/Products/KND22BC.html
You can not dim wire wound trannies with a standard dimmer. You need an inductive dimmer for this to work.
I have found an IQ intelligent dimmer switch in the same style as yours.
This is suitable for use with both electonic and wirewound trannies, as well as all standard lighting loads. (It's not cheap though)
http://www.tlc-direct.co.uk/Products/KND22BC.html