TV Viewing Flexibility

I have had fitted the TV wall bracket that was supplied by AS with my 2017 Symbol which comprises a small plastic mount on the wall and a fitting screws to the back of the TV.  What I am looking for , without any luck, is a more flexible/manoeuvrable un it for the TV that fits on to the current wall plate.  I am also looking for a wall bracket that fits the existing wall mount that will take an iPad.
I know that I can buy both the brackets that I require but wanted to reduce the number of holes that I drilled into the wall by using the back plate already installed !  Many thanks.  Bill