I don't think that the offer of a refuge placement is extreme and I think your dc will enjoy being in a safe and warm environment with other dc where they won't be repressed or shouted at simply because they're children who are powerless to take on adult bullies and best them.
The adantage for you of being in a refuge is that you will have all the help you need to apply for benefits etc, begin the divorce process, obtain any necessary injuctions, and may be given priority for council/social housing. The latter means that you won't be subject to the vagaries of the private rental market with the ever present possibility of having to move at a few months' notice and this opportunity is not to be sniffed at.
However, it's unlikely that a refuge placement will be within commuting distance of your work but, as you will presumably wish to be permanently housed near your dm, it could that your employers will grant you leave of absence for the necessary time it will take before you're rehoused.
The alternative is that you stay put and make your h leave either voluntarily or by means of an emergency ex parte application for an occupation order and a non-molestation order if whatever solicitor you instruct considers this to be in your best interests and I suggest you get back to WA and discuss this possibility with a dv worker.
The good news is that with £11,000 in the bank your h is well-placed to move out and stay in a hotel or similar until he can find a property to rent. The bad news is that this necessary expenditure will reduce the sum you're entitled to claim from his savings as part of the division of marital assets.
I advocate for abused women to stay in their homes and for the removal of their abusers using legal force if necessary, but I would advise you to take the quickest route to being able to assure your dc from your earlier relationship that their tormentor has gone from their lives and they will NEVER have to see him again.