Tom , this relay diagram... things got a bit messy around that year onwards towards the injection shell production and you'll find the diagram on page 339 of the haynes manual applies to your wiring ,although it says fuel injection models, its not just those.. its carb ones too... on the body wiring that is.Its item 77. (the manual I'm looking at goes to 1993, but I'll check the later ones page number when I get it back from who I lent it too)
I had a similar confusion on my '93 carbed mini. I have had problems similar to yours and it turned out to be some stupid awkward inline fuses under the dash behind where the orange relay is. They become hot and melt creating an intermittent contact .They were changed for blade type holders and fuses and have been fine since . Another other problem was the stalk on the column also . Fuses account for the majority of the minis electrical problems and its worth investing time into changing the main fusebox, if it hasn't been replace recently, either with the original type or the later blade type.
Hope that helps mate. If you still can't find the diagram ,get back to me and I'll copy it for you or drop in to see me if you are local.
Best of luck
Steve
