Bookworm sorry to hear about your head, hope the bump is going down and nothing further develops. I don't know much about ryanair configurations or which rows are designated as emergency exits on that type of aircraft. However regulatory authorities often stipulate the proceedures to be utilized as they apply to exit rows.
On your final point, I am assuming you are referring to the flight deck crew. With respect, it really isn't their job to remind passengers to take care when opening overhead bins at the end of every flight. In my experience the cabin crew usually do make such a reminder ( I know they do in my company ). It is really not necessary or desirable that the Captain or F/O should then repeat it. We don't repeat the safety briefings just in case anyone decides to ignore those. That is one of the reasons we have cabin crew.
Another point you might not be aware of is that taxying in after landing is not a time for the flight deck to be making P.A's. Although not necessarily the busiest portion of the flight, it is still a busy time and there is a need for concentration and cross monitoring. Additional look out requirements are needed as you have now have ground vehicles mixing with aircraft. Careful monitoring of R/T is also vital.
I agree that a few passengers seem oblivious to anything they are told ( particularly if they feel the rules don't apply to them.) Crewmembers on a flight are assigned functions and it is not a good use of resource to have the Captain or F/O repeating everything in order to impress those that won't listen.