Just seen this thread.
From what I can remember the Uproar had a black fuselage and yellow nylon/silk covered wing/tail. It was a very long time ago, so I could be wrong! I used to fly in Sussex and often went up to see Harry Brooks practicing for the 62 world champs. I even helped him out with some building and repairs on The REB that he flew in the champs. We all used to use coloured silk or nylon in those days for covering wings so I expect this is what Chris Olsen did with his Uproar to keep weight down.