No, not when ‘a man of his learning and devotion’ is so obviously off the mark. Now I like C.S. Lewis. I have learned much from him over the years. The Chronicles of Narnia (The Magician’s Nephew is best read as book six and not book one), the Screwtape Letters, Mere Christianity, Till We have Faces, and others have been challenging and instructive, but I don’t have to agree with him particularly when his belief in purgatory is based primarily on opinion, it would seem, since he cites a poet for support rather than scripture.
Take this, for instance, from your quote:
There, if I remember it rightly, the saved soul, at the very foot of the throne, begs to be taken away and cleansed. It cannot bear for a moment longer 'With its darkness to affront that light'.
The main problem is this:
the saved soul……… begs to be …… cleansed
The apostle John wrote in 1 John 1:9
If we confess our sins, he is faithful and righteous to forgive us our sins, and to cleanse us from all unrighteousness.
A saved soul is cleansed
He took on our unrighteousness so that we could take on His righteousness. That is the only way we can be acceptable to a holy God. When we stand at the throne, we will be clothed in His righteous garments and not our own filthy rags. To grovel at the thrown begging for more cleansing is telling the Father that the blood of His Son just wasn't quite good enough.
As I said, I would hesitate to simply dismiss someone that we all know to be a serious scholar, a man learned in Scripture, and a devout Christian, just because his personal interpretation disagrees with yours. Is everything he brings to the table worth nothing?