Thanks Nigel for your very generous response and thanks Egol for your confirmation as well.
We do have a small team and we are not dominating rankings in our sector yet, so your point is well made. From what you are saying, it seems there are no technical limitations in terms of search engines penalising the under performing site (originally it was a copy of the main site). It seems to come down purely to a well constructed, designed and marketed site.
So thanks again for your really wise words - it has been an enormous help
Marc