Out of control grandchildren

Please help, I know I will probably get a roasting from devoted Grandmother's but I need real advice because I'm at my wit's end.
I have 3 grandchildren let's refer to them as J, O and M, 2 boys J and O and a girl M.
My DH and I had 6 boys of our own, they were such good kids, if we took them places they behaved so well. When I look back I think just how lucky we were.
Now I will tell you about my problem.
Every visit from my grandchildren is becoming a nightmare.
The first thing they do is run into the hose, screaming and laughing, that's not unusual you might think, they are excited and pleased to see us but the running around and screaming don't stop for the whole 3-4 hrs they stay, I hardly have chance to talk to them.
I catch hold of their arms they look at me as though they have been traped, I ask hey J come tell Nanna how school was today. J looks at his arms, tears himself from me and runs of.
I then go after him, he runs back into the living room. I say tell me about the story teacher told you today. J looks, he says bananas, I say oh yummy I love bananas especially in a sandwich, he then says to me banana and poo, I say no bananas is nice on its own. J runs of shouting poooo. Now his sister M is running back and forth during this time, screaming, jumping on to the sofa, kicking her feet and knocking over photos I have of them. I say oh be careful we don't want to break your lovely photo you gave me. She turns around and says, poo, she comes to me and she says your bum smells like poo. Her mother just says oh M she's no lady is she and just laughs, all this time DIL just sits on the sofa, telling my son to see where they are.
That's another thing that amazes me, my son who was so sensible has in my opinion been abducted by aliens ( his wife's family) and had his memory totally wiped because everything we taught him has just gone out of the window, his wife and her mum, who I think I should add was a midwife has him totally under their thumb. Oh by the way would a midwife encourage her daughter not to sterilise a new baby's bottles and feed him a full cooked Christmas dinner at just barely 2 months old. Later he had terrible tummy and bowl problems, the doctor thought he was intolerant to lactose but I knew the problem was the way he'd been force fed. Even her mum told her not to tell the health visitor she was feeding him solid foods. I tried to advise but i got, "Oh my mum's a retired midwife so........." yes I'm afraid my advice went in one ear out the other, even though I had 6 very healthy boys.
So back to the mad episode.
Now while J and M are running riot I have the third one O who has a soaking wet nappie that has leaked out on to his trousers and they forgot to bring extra nappies so I go and find an old town and say you can use this to put on him for now, it's old so you can chuck it when you get home. (mentally making a note to buy some nappies just incase this happens again)., well O is absolutely going crazy, starting to bash the radiator with his toy robot, my DH stops him straight away, he now turns around and starts hitting the table I have my glasses on, I grab the robot quick, O screams and we are in a tug of war, I say careful your going to break your robot, he just screams and shouts my robot.
I say stop pulling and I will let go, if you keep pulling you will fall and hurt yourself. I let go he falls, now he jumps up and runs to his mother, looking at me like I'm an ogre.
Meanwhile the other two are running around back and forth the kitchen, I bring them back to the living room and shut the door, they run to open it, I say 'no' they catch hold of the handle and start kicking the door. In all this time their mother just says oh M oh J oh O, she don't get of her bottom to stop them, I stop them and she looks at me like I'm a fussy old spoilsport.
This happens every birthday, holiday, Christmas, anniversary. It is making special days a nightmare.
We used to go down to their house to visit, it was always a strain, there was always toys, dirty nappies, dirty pants, blankets all on the floor, you had to step over everything to get to a chair, I would start picking up everything, my DIL would look like oh my god what is she doing.
When we were visiting it was much easier, I had control on how long we stayed, which was about 1 hr because it's about all I could bear especially when M whispered in my ear "I want you to go home now", the reason being they wanted to watch TV but couldn't because we were there.
Now as my DIL recently passed her driving test, they now come up and visit us and they stay for hours, in fact I have to say, I think the little ones are getting tired, my son takes the hint and says right everyone get your shoes on. Now it's a fight to make them sit and put their shoes on.
Meanwhile, I see my DIL sitting on the hall radiator while she puts her shoes on, I am lost for words, she is about 12 st, the radiator grill is bending under her weight.
They go outside, J starts kicking the porch wall, he then gets put in the car, now M is in the car screaming, O still has his wet his trousers on, now the child car seat is all wet.
They go, we wave, smiling, we go into the house, I cry.
This happens on every visit, it's becoming a nightmare. If only they talked to us, played with toys nicely or sat and read a book with us I would be happy.
This is a time when we should be enjoying our grandchildren, but they are so rude and hyped up every time. We can't enjoy their visits. Before you say it's sugar, they dont have sweets for that purpose but it's not made any difference.
Please help, are we just terrible grandparents feeling this way? I'm at my wit's end.