however "time barred" as far as i am aware dosent mean that they cant chase you for the debt or that the debt disappears, it just means they cant give you a ccj for it. i also have the feeling that government debts do not become statute barred in the same way as other debts. In England, if you fail to inform them of a new adress, "statute barred" dosent work.
you have have a lot of different advice on this post, and of course you want to believe the advice that says you don't owe it, or that you can get out of it in some way, but it might be better to take legal advice, or CAB for a definitive answer