I got to Morrisons on Monday only to find that it isn't a 24-hour store (the horrors!), and that it was therefore closed. Therefore, I can't provide a list of this week.
This raised the question: if they aren't open when I want to do my weekly shop, should that automatically disqualify them from consideration? Given the choice, I would prefer to do my weekly shop on my way home from band on a Monday, and if they can't provide that, why not take my money elsewhere?
At length, I decided to relent. In the event that they are significantly cheaper than the alternatives, then I'll move my shopping day. However, this does automatically place them at a disadvantage - if it's marginal, then convenience will work against them.