Can anyone advise me if there is any situation when HB/CTB backdates can go beyond the 52 weeks or is that the the maximum regardless of circumstances.?

If you are talking about a claim for backdating then 52 weeks is the maximum no matter what the circumstances.

However, if you are talking about an increase in an existing award, then there are some circumstances when this can be applied retrospectivly for more than 52 weeks.

cheers , thanks for your help.

If the claimant is already recieving HB a review to correct official error can go back beyond 52 weeks, but that has to be proved as such (see shelters guide to housing and council tax benefit 2007-8). I have got backdates beyond 52 where very good cause can be shown but you are best to have lots of backup evidence to justify it.