So I saw your update for IOS about reminders, and in doing so made some edits to use the Odometer for my car so they trigger properly.
In doing so I saw the note that a Service type has to be set correctly for the reminder. So I had a look at a Note I'd set up for Road Users Tax. I went into the entry and changed the Sub type to Road Users (new custom type). Then saved. When I went back into it, the sub type was empty again.
So I went to my iphone (I use vehicle tracker) and couldn't find the entry in the logs...worked that out, it doesn't show notes. Back on the web site changed the note from a vehicle expense to a Vehicle Service. Now it shows up in IOS. And lo and behold it has Road users as a service type.
A couple more service entries (for registration, and for a fix to my doors), IOS shows the service type, the web site doesn't.