PLEASE instruct your solicitor to apply for the two VITAL emergency Court orders on Monday or very shortly thereafter.
If the application is made ex parte your h will not be served with notice of the proceedings before the Court hears your case; after the Orders have been granted, he will be served with copies and given a date, usually within 28 days of the application, for a full Hearing of the matter at which time he can enter a defence against their continuance - I feel confident in saying that, given the circumstances, any defence he files will fail.
I understand that you are scared that obtaining injunctions against him will anger him but as for 'backing him into a corner', I trust you will see that it is his actions that have backed you into a corner in which you have no choice but to take this action to protect both yourself and the dc.
If, after he has been served with the Orders, he remonstrates with you simply point out the above - if necessary, repeat ad nauseum until the message get through to him - and then simply adopt the tried and trusted 'all I've done is act on my solicitor's advice and if you have a problem with that please take it up with him/her direct'.
As for waterlego's very kind offer to facilitate contact in her own home, IMO this would place an unnecessary strain on all of the parties concerned and I would therefore suggest you insist that, for the foreseeable future, all/any contact takes place in an entirely neutral environment such as a play centre, childfriendly cafe, etc and that waterlego accompanies you - if she is willing to do so.
I would further suggest that you do not engage in any conversation with him in respect of your relationship, whether past, present, or future, during any contact sessions.
From what you have said of his current state of mind, it may be that you are best advised to ensure that any communication between you conducted via your respective solicitors until such time as he is able to comprehend the full implications and ramifications of his behaviour
Re Social Services visit to your home yesterday, what has been their input with regard to the dc? SS have the power to request him to remain away from the home but, unfortunately, there can be considerable regional variation as to whether ss departments are willing to exercise this power and you may have drawn a short straw with your local authority.
With regard to your dc having contact with their father, you should be led by them and if any of the dc do not wish to see him at the present time I would suggest you accord with their wishes and do not attempt to jolly or otherwise coerce them into seeing him.
If any/all of the dc express a wish to see him, any/all contact must take place outside of their home until both they and you are confident that he does not present any risk. As I suspect you are beginning to understand, it may be a very considerable time before you are able to reach that point and, in the interim, it would be extremely unwise for you to rely on any promises he may make in this respect.
With regard to use of the car, I would suggest you take the train which should not present too many difficulties providing you can rely on a friend or organise a taxi to take you to the nearest mailine station for direct rail travel to your destination and pick you up on your return.
Given that you are planning to be away from home during the forthcoming half-term, I would STRONGLY advise and urge you to obtain emergency injunctions at the very earliest opportunity as, no matter what verbal assurances he may give, it is probable that he will use your absence to reinstall himself in the marital home.