Nick
I have used Avcom AC-200 for about 10 years (Same pair - no problems) I bought them in the US.. You dont say where you are doing your training, but if the USA then buy from the pilot shop there.
I found the AC200 to be ideal, as the company apparently make the ear muff shells for the likes of Dave Clark they are virtually identical. They are robust, reasonably comfortable, have reasonable sound attenuation, and are competitively priced.
As they were cheap, I bought a second pair after five years of good service from the first for passengers.
Cheers
Mark