Switched live tap from back of the fuse box

[JeromeC]

Hi all

I want to "create” a new switched live circuit to power a Bluetooth amp (io-play) and an iphone charger. I’d like to use one of the empty fuse slot in the fuse box (eg heated seat).
Does anybody know which one of the plug (on the little panel behind the fuse where all the harness are connected) corresponds to the heated seat fuse? And what the pin-out is?

Many thanks

Jay