Double Dimmer Switch Change

[housby]

I changed a double dimmer switch at the weekend after one of the sections, for quite some time, had ceased working on the old one.
Although the back of the new switch was different to the old one I managed to get the job done (sort of). There is a short piece of wire inside that runs from one terminal to another which I suspect is the one completing the circuit on the house extension (this is on another circuit to the main house). The thing works but I have discovered that sometimes, quite often actually, I have to hit the on button 3 times (consistently 3 when it happens) to get it to come on. This is with BOTH sets of lights as well.
The question is: have I somehow got the wiring wrong (in which case why does it come on at all)? Or could the new switch just be faulty? Please note that this happens less often if I remove the buttons and just push the plastic switches. Never seen anything quite like it before.

 

[EFLImpudence]

If it happens when the buttons are removed, I would think they are faulty.

Do they sound like they are clicking as they should?

 

[housby]

If it happens when the buttons are removed, I would think they are faulty.

Do they sound like they are clicking as they should?

They do click yes. I have since had a word with B&Q where I bought it and they have suggested I return it and get a replacement as they, as I assumed, said I can't have wired it wrong as it wouldn't work if I had. They also agreed that a loose connection is unlikely as it is amazingly consistent at 3 clicks, although sometimes it does work normally. It is BOTH switches as well, not just one. At the very least if I exchange it if it continues I can then rule out it being faulty (unless it is a design fault of course).
It is strange but I will come back on here when I have changed it (it might be a few days before I can exchange) and let you know. Thanks for getting back and if you think of anything else in the meantime please let me know.