Halifax broker gone into administration, page-15

For retail investors only CHESS or issuer sponsored holdings can be transferred easily to another broker within days for sale. Any other arrangement will involve trust accounting of some form, which can be subject to freezing, fraud, or other malfeasance. Your shares will then be stuck there till investigations are over. From what it seems here, there should be no issue in getting all or most of the holdings back, but it is just not worth the risk and worry during the delay,. 

I personally wont use anything else, especially when CHESS brokers have very competitive fees, and many allow for Metatrader access.