Ian Raby ran a standard Cooper for 1953 (possibly the Mk IV referred to in the advertisement) but for 1954 he built his Cooper based special, often referred to as "Puddle Jumper" a name Ian used for many of his cars. Ian appears to have only run the car for one year before reverting to a production Cooper once more.
Ian achieved some respectable if unspectacular results with his special including:
In 1955, the car appears in the hands of Trevor Shaddick
If you have any more information, please get in touch!