So the idle problem returned a week or so later and in consequence I thought I'd better bite the bullet and get a new ICV - dealer price circa £200 and only available in Germany, which I thought was a bit (lot) too steep. So I did a trawl of various US sites and discovered that the Motorcraft part number for a 3.0 V6 Escape ICV was CX1899 and that it was available on Amazon from the US for £50. Ordered one and it arrived from the US a week later. Compared it to the original and identical including manufacturers part number (3F1E-9F715-AC FK13). Fitted and checked over several long runs and all appears fine. Sailed through the MOT as well but now wondering what next albeit still great fun to drive