After reading this I thought that giffgaff could have a "giffgaff shop forum" in the community where people can put posts just about the shop on topics like "merchandise ideas", "payment" or thing like "updates from the giffgaff team in the shop" or "service updates for the giffgaff shop" if something was to go wrong. (which hopefully it wont!)
This could be a good idea as people would be able to spread their thoughts on the giffgaff shop all in one place, find out whats going on in the giffgaff shop, or other things like suggest improvements for the giffgaff shop and pretty much anything related to the future giffgaff shop!
This may not be implementable by the 23rd April, when the week long shop will be active, but from the thread above it is stated that there probably will be a permanent shop in the future and this "giffgaff shop" forum idea could come into play for when/if the permanent shop or any other temporary shops open on the giffgaff website.
Here is a quick picture I made of what it could look like: