Well thanks to a fellow AC 2 litre owner and knowledgeable source. I now know what to take off. Undo the tool box/hatch lid hinges gently prise off the bottom ply panel (on mine it was pinned all round the edge), and hey presto there it is, just undo the nut carefully after a good squirt of wd40. There is a little pin on the badge as well that helps to locate it the right way up, a gentle prise and away it comes after years of polish and road grime etc. All good now to the rubbing down etc etc.
Cheers G