Hi Nigel,
Thanks for such detailed response. I am afraid that we may hurt ourselves after reading your answer. But we can see many websites which have got number of links from their sub domains, infact from every page of their sub domains and I don't see them penalised.
And what is wrong when we try to divert users from old content to new content? We can see this been employed by many websites when they have something to feed to their customers.
If you are sure about the risk, I would like to get your personal suggestion by looking at our website if you can.
Thank you