Using Store 1.6.3 I have only two shipping methods: Collect in store (free), or UK flat delivery fee of £4 per order. When a customer chooses the delivery fee, but then unticks the Shipping Details are the Same as Billing Details, and adds a different shipping address, the method name doesn't change, but the value goes to zero (should stay £4)! I have tested this myself using two UK addresses and sure enough, the total reverts back to £4 once my shipping and billing addresses match. The live site: http://www.thirstymeeples.co.uk/
Any ideas what causes this? Thanks!