MPC was the American distributor of Airfix kits for quite a while back in the sixties and seventies. Kits in MPC boxes generally are identical to their British counterparts; the only differences I can recall were the colors of plastic (I once bought an MPC H.M.S. Victory that was molded in olive drab) and, in some of the aircraft kits, the decals. (For a while, toward the end of the arrangement, MPC was putting some bizarre "custom" decals in Airfix 1/72 aircraft kits.) I wouldn't hesitate to pick up an MPC version of an Airfix ship, if the price was right.
The Airfix Iron Duke is indeed a nice kit. The biggest problem I recall was that, for some reason, the barrels of the secondary armament appeared to have enormous donuts slipped over the muzzles - but those could be sliced off. I believe White Ensign offers a set of photo-etched detail parts for it (probably an enlarged version of the fret that was made for White Ensign's own 1/700 resin version - now, I believe, no longer available).
I've been complaining for years about the plastic kit industry's failure to pay attention to WWI warships. If you're particularly interested in that period, you owe it to yourself to take a look at the line of resin kits from the Russian company Combrig. Excellent quality (especially the more recent releases) and, by resin standards, extremely reasonable prices. A good way to check them out is via the Steel Navy website: www.steelnavy.com.
Good luck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.