The best thing to do is to go into a local branch and speak to someone in authority, senior customer advisor or even manager
tell them your situation and explain that you need the overdraft facility restored for a SHORT period of time
you've got to offer them an insentive to give you the overdraft back; so my advise would be to ask for a reducing overdraft. say you can afford to pay back £100.00 off the overdraft each month, so next month it will be £900 overdraft, £800 the following month and so on.
the thing to remember with overdrafts is that they are only meant as a temporary measure and are not to be lived in
Matt