first of all i'd like to say that i know this isn't a massive problem when compared to those that others go through with their exes but it's something i need advice with so i'm posting here as other may have experience and know what i need to do. i dont wish to be insensitive by posting about small things when others are going through so much more. 
Backstory: exp is in the forces. he sees dcs when he is on leave, doesn't give me any notice of this. he just texts the night before or that day asking if they are free. he never commits to a time of when he will have them back, sometimes he will commit but is always late, sometimes by half an hour and he wont text to warn me. sometimes he will text me ten minutes after he is due back to ask if it's ok that he keeps them another hour or two, even when i agree to this, he still drops them back after the newly agreed time. the thing is i dont work ATM and i feel he knows i dont really have anywhere to be so i will just be in the house anyway and i feel i cant really justify saying "no, we agreed a time, stick to it" because there is no real reason why they cannot be back later as i really am just in the house.
so current problem. his messages to me have been getting over friendly. i dont like it. i dont encourage it and when they start getting like that i stop replying. i only text him when it's in relation to the dcs and him collecting them/dropping them off. i thought i could manage this but tonight he turned up unannounced at my door. i definitely do not want this happening again. not a big issue but i was in my PJ's and dressing gown and we were in the middle of dinner, of course the dcs got all excited and thought they were going to his house. he says all he called for was to ask if he could have the dcs tomorrow. he could have texted. i dont care if he passes my house ten times a day, i do nOT want him thinking he can just turn up here. it really caught me unawares and he actually called me a lazy bitch (he was joking but i dont appreciate it) because i was in my PJs. i do not want to be living in edge all the time incase he calls. he is crossing boundaries and i can feel him trying to build up to get close. (there is a history of him breaking into my house, going through my personal things and he even punctured my entire condom supply when he found out i had a new boyfriend)
as if this wasn't bad enough, he is due to leave the Navy mid feb and will be home full time from then on. he said last year that he intended to have the dcs more and hoped to have them every other weekend. i would prefer he had them more TBH but i know if i push for that he will take them even less!
so i need advice on how to re-establish the boundaries now. his friendly texts are getting ignored but i need to let him no he is not welcome at my door uninvited. i also need advice on how to take control WRT the whole being on time, not abusing my time and being consistent with him having the dcs for an agreed period every week/fortnight. history has shown me that although he says he wants the dcs every other weekend, i know this will in reality be more like him texting when he can be bothered to have them and me and the dcs will just have to hang about waiting for him to arrive/drop them back. i want fixed times agreed on and i need to be able to get him to stick to them when he (inevitably) starts to stretch the time frames.
any advice greatly appreciated.