I know on a previous thread several people mentioned they were easy to fit yourself but I wouldn't want to do any damage so I left it to the garage. Would not be without them, I am sure they have made a difference in this mucky weather. The prices KugaBabe mentioned were around what I paid.
checked out your pictures BigGeord mud flaps look fine to me gonna get me some i also got some nice shiny black door gaurds from halfords £ 3.99 for 2 as first time my daughter got out the rear door only had the car 4 hrs she bashed it into the brick party wall agggggggggggra !! they go nice on the panther black and arnt that noticeable.
it has child locks but I don't like them because I also have adults in the back of the car many times.
but for bumping the doors into a wall or another car there are other solutions (door protection or extra child education/raise