"I may bump that out a few years myself as there is just so much going on that merits being written about."

Meaning : more of the "Stone Gryphon". O yes ! Please do that :-D

Time running longer in Narnia : in fact, I like the idea. Why would the time be exactly like on Earth ? Different planet/world, different length of days, months and years. Earth is OUR norm, but not everewhere's norm ! :-)

But I understand your frustration, and I myself tend to add years in my imagination to the Pevensie's reign.