Hi gazzauk80, welcome to the site.
It is certainly a posibility which is why this site would generally advise you to open a 'parachute' account in advance of taking any action. It is becoming an increasingly common option for banks to pay out and then to state that they feel 'the relationship between the bank and the customer has broken down' and they have no option but to close the account.
A number of people are exploring whether this is a legitimate action and whether they can be stopped but my guess is that for the moment you should at least be prepared for the posibility.
Look on the bright side though if (when

) you get the charges back you will be able to repay a chunk off the outstanding amount anyway.
Read the faqs and follow the process and post back with any other questions - there are lots of very helpful and knowledgable people about who will pitch in.
Cheers