Many thanks Chris.P for his hint on cleaning new tyres with some brake cleaner following a previous thread.......
  Bad Friday..........  I took my new Corsa's into work and gave them a good going over as Chris suggested .... I was using a new white cloth and the deposits/oil etc that came off was surprising, the cloth soon became completely black! 
 Shame about having to buy a can of cleaner from Halfords when I work in the petrochemical industry....can't I just slap some ethelyene on 
  Dont worry - I know !!! 
 Cheers Chris