My wife got back today from a few days away in Leicester without this bit of the car. So I got on the phone to my local shop and ordered a new one. Will take about 4 days to get it done as the rear plate is special order, and mine for £25. If anyone finds the original somewhere between Leicester & Plymouth please send me a pm!!!
She also reported back that the new tyres I had fitted last Thursday developed a wheel wobble at 58 mph feeding through the steering wheel, fortunately it went away at about 62, so she was relatively unbothered on the motorways. The car otherwise was fine and returned about 45mpg on her 550 mile round trip.
She took into the tyre shop this afternoon, they rebalanced it and all now is ok.