Today, 17 February, I have just returned from my dealer after checking for myself the results of the wheel swap, see my post 15th February. The donor RCZ fitted with the wheels from my R with Goodyear Eagle tyres did produce the knocking and vibration, though to a much lesser extent, however the temperature today is not so cold. My own R fitted with the donor car wheels and Pirelli tyres did not produce any knocking or vibration. I am now 95% certain that it is a tyre issue but am surprised that this has not been picked up by Peugeot UK. The dealer has agreed to replace the two front tyres with Pirelli P Zero and I will pay the cost price to replace the two rears. The service manager said they have a 2008 coming in with a similar problem, so will be interesting to know if that is fitted with Eagle tyres.
I would like to take this opportunity to thank my dealer, Portfield Peugeot, Chichester, West Sussex, for all their help in trying to resolve this issue.