Power to Outside

[gimli]

meaning lighting applications which run off DC although I understand that the transformer will still run from AC source. Its just something we have implemented throughout the house and would like to continue to use outside

Thanks

 

[ban-all-sheds]

meaning lighting applications which run off DC

That's probably extra low voltage. Low voltage is up to 1000V.

http://www.diynot.com/wiki/electrics:voltage-bands

although I understand that the transformer will still run from AC source.

... run armored cable outside to a socket location

Is the transformer you've chosen designed to be plugged in outside?

I will go for labour only so an idea of cable size etc would help me get a price idea.

You do know that he'll be able to get the cable for less than you will?

And as for "labour only" - you've not contacted any electricians yet, so how do you know that you'll find one happy to work like that?

This work is notifiable, so you'll be needing the electrician to say he did it all, including choosing the size and type of cable. So you should let him.