Thanks for the reply.
Ater posting this I searched the web and actually found a 
software which actually does this. i.e. downloads the tree 
structure. AUBUS is the name of the program, I think I 
downloaded it from download.com. I have not yet completely 
tested it so can not say much about it but on the face of 
it , this seems to work
How I wish HTTRACK will do he job
cheers