From what I can see those amazing shoes are Jeffrey Campbell's Lita Spike ankle boots. You can find them here at Office.co.uk
Thanks to everythinghollyaoks.tumblr, you can steal a bit of Sinead's style too! Check this outfit worn by Stephanie as she plays Sinead:
The leather jacket is available at: TOPSHOP
The side studded tote bag is available at: RIVER ISLAND in blue (black has sold out!)
The dress is available at: ASOS (in sale, snap it up quick!)