In this toccata, Vierne is - IMHO- at his best in the "dark energetic mood". It could evoke things as Chopin's Prelude n°16 (in b flat minor too) or some of Schumann's agitated Kreisleriana.
The Caen version is slower than indicated on the score, but I "feel" spontaneously the piece like that.
I added (at 4'20) a recording on Hereford made with two aims :
- see how it can sound on a typical English cathedral organ
- try the score's tempo.
The Hereford result, which mixes two takes, is a bit hectic with an unstable tempo and slips. No use, but for the English sound in Vierne.