What happens to the ATC mor's do you actually get anything back after filling one in?
The pilots ones disappear off into black hole never to be heard of again. The vast majority of the ones I have done have all been tech related mind you.
Well, the unit I work at our own Safety and Investigations department do most of the follow up action and we get feedback on every report filed from them.
Otherwise with regards aircraft, to the best of my knowledge, under 5,700kgs the feedback from the CAA is made available on the CAA website.
Airline reports, see this Airworthiness Communication for how they should be reported back to your company and ergo onwards to you (assuming you work for an airline).
http://www.caa.co.uk/docs/33/AIRCOM200919.pdf
Bar one or two incidents over many years where CA939 action was involved, I've never had any direct contact from the CAA regarding any MOR I've filed.