You want to get a Costco account and have it delivered to you -
https://www.costco.co.uk/Grocery-Household/Grocery-Delivery/Southern-Comfort-1L/p/24798
You are limited to 6 x 1 Litre bottles but, even with delivery it works out at £17.33 per litre ... I took delivery of 6 last week
Even better for me given we have the stupid Minimum Unit Pricing up here so the lowest a litre of SC can be sold for is £22.75 (65p per unit MUP and 35 units in a litre). Because I buy it online, I get the same price as England and circumvent the MUP
