I do live up north - i'm in Stockport - and have been to Boundary mill. From memory I think they sell the tarts at less than £1. and they also have a Fragrance of the Month which they reduce by 25%. There is also an outlet near me in Reddish - Broadstone Mill - which also features a Fragrance of the Month but otherwise the prices are the same as everywhere else!
I ordered a preview set of tarts from Yankeedoodle of the new Autumn fragrances and was a bit underwhelmed. When I opened the bag there was just one smell that I could detect which was the Mackintosh Spice that overwhelmed everything else. So far, I've burnt the Almond Cookie which is lovely and at the mo am burning Farmers Market which is a lovely fruity/spicy smell. Have a feeling that all the rest are going to be fruity/spicy smells as well though!