Dimmer switch

[SAWbob]

Hello
I am new to the site and I was wondering if you guys could help me....I have just moved into a new house and the dimmer switch in the lounge will not turn off. It will dim but when you push the dimmer switch it will not deactivate it stays on.

I have taken a couple of photos of the switch and the wiring looks confusing...

I have the grey going to L1
Black and brown to L2
And the brown (assuming Live to the common).

Is this wired up correctly?? Its a 2way 1 gang switch controlling 7no 50w GU10 spotlights

I am a joiner by trade (for 26 years) and worked in the facilities management business 10 years ago where I got my 16th Edition but haven't touched electrics much sin over 5 years so I was hoping to get some advise??

Cheers in advance.

 

[telectrix]

that buried choc block looks suspicious. i'd dig it out.

 

[SAWbob]

When I isolated the lighting circuit the kettle which I was boiling for a brew also got isolated.....so I reckon some ropey wiring has been installed here.

I will get a photo of all cables running into the back box and post a picture