Stuffing I've only just seen your post.
I spoke to a solicitor on Tuesday, we discussed PR, threat of abduction, what to do if I allowed contact and he refused to return the DCs etc and I felt a bit more secure HOWEVER every day he has text/left voice mails accusing me of preventing him from speaking to the DC on the phone. I have not done this at all, I have spent the week doing school/nursery drop offs/pick ups, getting food shopping, sorting out benefits, ferrying DCs to different appointments and activities etc etc. All with no car and in bloody treacherous walking conditions. BUT he expects me to be available the minute he decides he wants to phone. When I return his call at the first opportunity he doesn't even speak to the DCs but instead uses it as an opportunity to be abusive and threatening. He has stopped sending it in text messages after I told him I was saving them. I know he is an impatient person and expects everyone to dance to his tune so I initially thought it might be that he is winding himself up when he cannot immediately get in touch with me but it's exactly the same if I answer the phone on the first ring. Am I wrong to think that he's not even that interested in the DC or having custody of them but is using this to get at me, hurt me and frighten me? Can a person be so sick?
I asked the solicitor about injuctions, she said to try to establish some regular contact with him and the DC, (obviously difficult as he is 250 miles away) and that his behaviour was probably a result of it being a very recent split and him being angry with me. So OK I agree and he has the right to feel anger, hurt or whatever but surely that doesn't give him the right to act in such a way towards me? Do I have no rights then?
I have been documenting everything, my mum is coming to the police station with me in the morning to report this and seek advice.
The solicitor didn't seem keen to do much in the way of preventing harm to me or abduction of the DCs. I'm going to go back to her on Monday, this time with my mum as obviously I'm not getting my point across strongly enough (and she will 
.
Tonight he called, my mobile was on silent as had returned from a birthday party with DC1 and I forgot. I had 9 missed calls (all in the space of 5 mins) and a text saying "when can I speak to all my girls", I called back gave the phone to DC1, she was trying to tell him about her visit to Santa this morning and birthday party this afternoon, I could hear him saying "put mummy on the phone" over and over and eventually she got fed up of him not listening and talking over her and handed me the phone. Then I got abuse about a text my mum had apparently sent to someone saying we had split and she is overjoyed about it. Now that is undoubtably how she does feel but not something she'd likely do, the only people to have a connection with both EX and my mum is my Dad and Step-mum. Turns out he had phoned my Dad 10 minutes earlier bleating down the phone about how he really loves me and I won't talk to him etc. WTF why call my Dad? I'm 34, what's he going to do? Ground me? Order me to go back? Also, my dad says this is untrue and he did not say this or anything close to it to EX.
I don't know why I'm posting all this, I feel like my head is all over the place and I'm trying to make sense of it all but I just can't. And I'm trying to work out if it's me. Am I the problem, or causing the problems, am i being deliberately difficult and unreasonable? Because he's really got me starting to think that I am.
I won't be answering the phone/door/e-mails from now on. During this evenings call he told me he will be coming up "sometime" in the week, him and me will be sitting down to have a "talk" and if things don't go exactly as he wants them to, or he doesn't get what he wants, then I am in for the "shock of my life" and he's going to "have the DC off me and in fact may just remove them from me there and then". He said I can call the police etc and they won't do anything as it's all perfectly legal.
Problem was that my DD1 heard this, afterwards she went upstairs and told her sister about it and that he was coming to take them away and they'd never see mummy again, and they were discussing hiding places for themselves for when he comes and where they will hide DD3 from him 
They are 5,3 and 2 FFS they shouldn't be subjected to this and thinking that way! I feel like such a bloody failure that as a mother my DC should feel safe with me. And they don't.
I am SO sorry that this has been such a long post and if you got the end of it, well I salute you.
Thanks again for previous advice x