This was an interesting find; I think it's one of the VCS-7 Spitfire Mk Vb's used by them to spot gunfire during Operation Overlord- they swapped their OS2U Kingfishers for them during the operation. I know there are other photos of their Spits- one being '4Q' that had a small swastika behind the entry door. What was interesting to me were the 6-stack exhausts; my question being- was this a Mk Vb with Mk IX exhausts or a Seafire II? (I have read that a mixture of Mk Vb's and Seafire II's were used.) Just curious! Unfortunately, the 2nd letter of the '4x' code is obscured and of course, no serial is given in the photo caption. I did find an article on the Spitfire website that stated that this Spitfire was a Vc, but hard to tell by the photo, I would think; I have posted a link to that article below.
Mike
https://defensemaven.io/warriormaven/history/america-s-spitfires-of-world-war-ii-abFeEtvGZ0qFMw8ahm6lxQ
http://spitfiresite.com/2010/04/spitfires-of-the-us-navy.html