By Josie Clarke, PA Consumer Affairs Correspondent & Lawrence Matheson A caterpillar cake taste test has seen Co-op knock Marks and Spencer’s original Colin off the top spot for its “ultimate combination” of chocolate, sponge and buttercream. The consumer watchdog, Which?, blind taste test of caterpillar cakes from eight supermarkets found Co-op’s Charlie, costing £8 for 660g, to be the finest, awarding it a 72% score and a coveted “Best Buy” recommendation. Which? said the cake “wowed tasters” with its “ultimate combination of rich chocolate flavour, moist sponge and soft buttercream”. Coming…