Vis-a-vis remembering to order stuff when in UK; we run a shared spreadsheet (stored in a shared folder in Dropbox), with a few tabs on. Tabs include UK shopping list, Overseas shopping list, Home jobs and Paradise jobs. When we're in one place and think of something, we bang it onto the speadsheet for action or prioritisation.
The UK shopping list always has certain stuff on, like water filters and some essential oils we use as insect repellents, but it saves a lot of frustration, and works for us.