LED bathroom mirror

Hi just bought a led mirror for bathroom with dehumidifier screen. Has a 200mm length of 3 core 0.75mm flex which then has to be wired to connector block.
Planning on taking power from lighting junction box above. Would I need to go buy a roll of same flex cable or could I use 1mm 3 core cable which I have a part drum already. Was looking to replace the cable from mirror for a full length so I had no joint but its more hassle than it's worth.
Cheers guys
Magico

 

Sorry 1.5mm 3 core cable i have

 

As long as you can Terminate it ok it should be alright but it will no doubt invalidate any Manufactures Guarantee? Can't you just leave this and use an Isolator somewhere above it - in the loft if that's above it?

 

Sorted now thanks. Took a spur from lighting circuit into fcu in the loft down to mirror. Using the 1.5mm 3 core I had already. Removed the old shaver socket whilst up there
Cheers

 

However not sure how these mirrors are supposed to work. Has a touch button to turn on lights but mirror stays warm all the time...is that right?

 

Not normally from my experience maybe it has a Thermostat built in?

 

Might be me. Think it was still warm because I've had light on for a bit. Guess once the lights on so is the demister plate.
Cheers mate

 

Whats the Red bit in the chase above the mirror?

 

Is was the terminal block joint...since been crimped and taped and filled into wall