Chrissa
I'm a bit confused. There is an interim charging order. Is that the charge you refer to as a "Registered Charge", or are there two charges (in addition to the mortgage) on the title register?
I've a vague recollection from one of your earlier posts that you were disputing the charging order. If you were, there should have been a Court hearing which would have resulted in it either becoming a final charging order or being cancelled. Did anything like this happen? If not, it seems unfair to you if you did not have an opportunity to dispute the charge in Court. Jenna (who I think is a solicitor) might be able to advise on whether you could still apply for a final order hearing.
As a generalisation, my understanding is that anyone holding a registered charge can prevent a sale, but that it is possible to go to Court for an order allowing the sale to go ahead even if the holder of the charge will not be paid from the proceeds. Again, Jenna may have more info., but your solicitor would have to be involved.