I'll second MATELO in having the opinion that I rather doubt icing in supersonic cruise at high level was the issue..not just because of skin temperatures but also because of the relative lack of water vapour/ super cooled water droplets/ice crystals at Concorde cruisng levels.
The effect of icing during the climb/descent and also approach, when the aircraft was operating pretty much the same way as a "common or garden" subsonic airliner will have been of more interest.