my neighbour has laid 5 ton sand and astro turf in back garden he says he has put in drainage but my garden is totally mush you can actually see the water running under fence honestly so bad cant use garden ps ive been here 20yrs and its never been liker this ever do i have any rights 3 children summer holidays no garden help
My first thoughts are to contact your local council re planning requirements and/or the water company that deals with drainage in your area.
I'm sure others will have more practical advice as I have not had any problems like this.
Good luck.