Hi Nicolas,
It isn't an XB due to the size, or a VIIF. The location will likely be Trontheim in Norway, where the 24th were stationed for a while.
The tops of the saddle tanks look a bit flat for a VIIC, as you have noticed. The tops of the saddle tanks on the VIIAs were, I think, flatter in shape than the VIIC - a bit like in this photo. The hull sides above the tanks were also angled the same on the VIIAs as on this boat. The 24th did have a few VIIAs, and I've seen VIIAs of the 24th pictured in Trontheim.
I can't really tell due to the quality of the image but might it be a VIIA?
Cheers,
Dougie