I've just done a weeks work experience with Mary King and so I learnt quite alot about what the grooms do etc. Its VERY hardwork and if your a hardworker I'm sure it would be a very rewarding thing to do.
I think most people want to employ grooms who can work quickly and efficiently and everything has to be done to a very high standard!! Depending on who you work for qualifications are less important and experience is most important.
I think it would be very worthwhile for you to do a few weeks/months (sorry don't know how old you are or how much time you have!) work experience for top riders or at different yards (racing, dressage or whatever your interested in) so you can see what life as a groom is really like.
One day I had to start work at 4.30am!!! because we were going to an event. That was for a fairly small show aswell, for bigger events they would have started alot earlier
and they finish really late. If you don't mind the long hours and hard work its AMAZING
I really enjoyed it but I was only there for a week
Feel free to ask anything else, sorry havnt really helped with the qualifications bit! But I really think experience is the most important!