TKR You are right and I have seen this too often to count. My plan is to get a seat close to the exit and then, if unsuitable folks are in the way, to trample them down. I am not joking.
If the airline did not get back to you (Customer Service in ALL modern companies are created to not get back to clients) then I suggest writing to the CAA. Now, I know that the CAA are as much use as an elderly couple with a broken leg in an exit row when the Evacuation Call is made ... but if the CAA do not give you satisfaction, you can write to your MP.