DH is running London Marathon today so as a family we decided to make a weekend of it. It was also my DMs Birthday yesterday which was a milestone one. She had originally said she wouldn't to do her own thing so we only booked weekend after she had said this. Fast forward and she hasn't booked anything and she decides she too wants to go to London. She says she hasn't booked anywhere as she can't afford it but is happy to come for day (2.5 hour train journey each way, we live 1.5 hours train journey away from London) and could we meet up. So DH, and our 2 children with ASD went. Kids argued so much, winding each other up and fighting so DH and I had to split yesterday and do different activities. We all met back up and also met with DM and had lunch, probably not somewhere that DM would have chosen but my priority was kids. Mum seemed ok and I got restaurant to make a fuss, sparklers on dessert for example. DM was dropping hints about wanting to stay, she could go on park bench etc and that she wasn't thinking about going home.I just wasn't sure if we could sneak her into hotel which I felt was what she was expecting and also, if I'm completely honest felt that DM was gatecrashing. I felt compelled to 'give her a good time' when I was already struggling to manage kids but I kept this to myself. DM is a narc and our relationship can be difficult.We then all argued about what to do next and it culminated in DM, DH and DD going off to catch open top bus and DS and I just stood there. DS had wanted more time with me as he couldn't cope with DDs behaviour (hitting, pinching etc) and we had already had a lovely morning at one of the museums. I really enjoyed the time with him as my time is normally taken with DDs challenging behaviour. So DS and I went to Harrods which was his choice. He was also loving the tube experience too. DH etc didn't go on bus as too expensive and were trying to catch me and DS in Harrods but phone signal was rubbish so I didn't know this. DS had then had enough so went back to hotel. DH and DM are ringing and eventually we talk once signal back. Suddenly DM is catching a 6.30 train and no time to come back to hotel. She is upset at not being able to say bye. DH arrives back 1 hour later with DD. He is ok but explains he was very stressed and had to push my DM into making a decision. He was already fed up at having to split up for a second time and then the added stress of trying to work my DM out and can hold of me. It just seems a bloody disaster! I have come back home with kids today as DS still stressed from DD so unable to cheer DH on. AIBU to have not let DM stay with us? Am I being mean?!