kw installations (west midlands ltd)

We had the old windows taken out, part of the wall taken down, so we could have french doors and new windows replaced. All looks nice untill you get wind and rain, you then have puddles inside the house, draught comming in down the side of the door. It seems either easterly or westerly wind and rain is when you get this. The builder says its because the top of the bay had rotton timbers insde that he noticed when doing this job. At that time He said not to worry as this would not cause any problems with the windows. He now says its because the pebbledash is old and this is what is causing rain to come in . So I would like to know if my windows should have some kind of flashing over the top of the window, down the side and on the sill. He has put led ( at extra expence to myself ) under the window as I told him we would be putting decking adjoning to the property.Our windows face south facing the sea and at times it can get blustery
The old windows did leak and the pebbledash was the same then as now.. What grounds do I have. Its awful because they look so nice and the person is a friend of a friend ! We are very upset, the fitter is coming back tomorrow. I feel sure this will be ongoing. Please help with advise . Thanking you in antisipation.
Shey

Thank you all for your replys. Well would you belive our Window man never turned up.. So were do we go from hear. I will call him again. Im not sure if he put dpc on the top ,sides or bottom. I did not want to watch him at work in case he felt uncomfortable. The window sits back4 inches. I have upvc with air slats all the way round the top of the facia. The first time he came back he took this down and sprayed foam down the two steel supports either side of the french doors, then put duck tape on the inside of the facia board and put this back saying this should do it. He said maybe the wind was blowing water into the slats . What I dont understand is I have looked at some vidios on you tube that show you this sticky tape that is placed all around the window to stop the leaking, could this be my problem. Sorry to harp on but this is causing me a lot of stress. I did get a certificate but not fensa. I will find it tomorrow as cannot get to the filing box. I know it was ligitamate. What can I do if he refuses to come back. Thank you to all
Shey

It's the front door of my home I wish to change which is an UPVC door.

It has a glass plane above, and to either side of it in its own sectioned frame