Park sensor problem after respray

Some of you may be aware that I have been having my S type resprayed, well, got her back today with a little problem, rear parking sensors only give 1×5 second bleep then nothing, now! Bearing in mind the bumpers have been off for spraying with all sensors removed, and obviously disconnected from the module. Question 1, should the battery have been disconnected before disconnection. Q2, would  this impact on seat belt sounder warning, as it now chooses to sound any number of times sometimes only 1 bleep, maybe 3, occasionally the full 6 you get the picture, as well as these two posers , I also had to reset the one touch windows. None of these problems existed before the car went in for spraying. There having it in for test in the morning so I would like to be armed with some prior knowledge. I am aware the S types are voltage reliant and when checked tonight showed 12.1v  at rest rising to 14.1v and i am aware that the 5 second beep on reverse selection signifies park assist non functional, so any ideas guys, module, sensor or what.The repaint, by the way was worth waiting for, pictures to follow.