Losing a magazine isn't worth considering simply because the Lee Enfield has proven itself in wartime very successfully. It has a 10 round detachable box magazine. How many soldiers who carried it were killed because they lost their magazine in battle?
Who's to say? Perhaps the soldiers who did lose their magazines were unable to report it to anyone but St. Peter.

Seriously, lets not forget the Lee-Enfield magazine was never intended to be removed from the rifle on a regular basis. L-E magazines were always loaded from stripper clips. Even at that the British soldier was issued a spare that was kept in his pack.* That's a big difference from this Ruger sans clip guide and designed from the start to reload from fresh magazines.
I've read a fair number of first person British accounts from both world wars. Excluding
A Rifleman Went to War (written by a Yank gun enthusiast serving with the Canadians) and
With British Snipers to the Reich, the Tommies I've read didn't make much mention of personal arms. Even the latter was somewhat bereft of weapon details compared to similar works by Americans. Couple this with the facts that in wartime there will always be plenty of spares from your logistics train and fallen comrades, I wouldn't take much faith in the fact we don't have a lot of reports of lost L-E magazines.
Contrast this with a lone individual trying to survive some sort of calamity that's forced him into using his Ruger Scout for defense. He can't rely on any kind of a logistics train. What are the chances he'd come across someone with a compatible Accuracy International magazine, let alone be willing to part with it?
*
British Enfield Rifles, vol. 2 by Charles Stratton, North Cape Publications, p. 53