http://www.insolvencyhelpline.co.uk/bankruptcy /cancelling-bankruptcy.htm
This gives you some info. on annulment. I don't see how you can apply for annulment if you haven't already paid off the debts (& bankruptcy costs) in full or given security for them. You can't give security - which will come from the re-mortgage - if you don't know how much has to be paid! (Don't forget it is not only the debts to be paid - the OR costs will probably be in the �000s.)
I think you need to speak to someone at a higher level in the OR office, or else you could ring the Insolvency Service Technical Help Line - no. is on their website.
The charge (which only applies to your husband's share of the house) will not be removed until the bankruptcy is settled - the annulment info. implies you have to get an annulment before it is removed. I'm not sure whether that is essential but it's probably a good idea to do it anyway from the point of view of future credit.