Bank changing - who/how to contact (COL)

I'm in the same boat - switched away from Tesco.
The redirection period has changed a number of times,
It used to be a fixed 13 months, but now operates on a rolling extension

The Barclays agreement at www.barclays.co.uk/help/content/BAR_9913023_Online0916.pdf lays it out (and I suspect is the same for all banks)

> In the unlikely event that payments continue
to be redirected to your New Account during the
13 months leading up the end of the 3 year
redirection period we will automatically extend the
redirection service and the term of this Agreement
until such time as there is a 13 month period when
no Direct Debits, Bacs Direct Credits or Faster
Payment transactions have been automatically
redirected by the central redirection service.

So 3 years, then rolling every 13 months thereafter so long as it's used.

Had a reply from BDO, 

'Thank you for your email. You can of course send us your new banking details. Please note that we will be writing to all investors and creditors in due course to request updated bank details, in advance of any dividend.'

Transfer of Tesco account is happening now so will wait for BDO to contact me before any dividend.

Of course they wouldn't rely on 4 year old bank accounts (that's me being over optimistic - it might be a few more years until distribution, if anything is left to distribute).

I'm still waiting for my Tesco transfer action, current accounts will be closed on 30th November.  Managed to arrange two DDs, but the second one is not coming out until 2nd Nov. In order to cash £125 from Nationwide I need two 'active' DDs  I hope the offer will still be on the table at the beginning of November.