Actually, I’ve just found the wonderful work by @spockfish on RoPieee, which somehow I’d missed before. Looks fantastic and this type of functionality would ideally be built into a distribution like that (leveraging the existing extension), as it would be suitable for use by less technically inclined people. However, this may come in useful for geeky DietPi users until that happens.
Harry, if there’s anything useful to you here, please do feel free to reuse it. Although I suspect you may want to rewrite from scratch 
.