The IWM has for quite some time been cataloguing the gun camera clips in its possession. The last time I trawled through all the listings to compile a file was in 2010 - I've just finished re-doing the exercise and the number of films listed has almost tripled in the interim. I believe the exercise is still underway, with more items being gradually added to the list (as in, the IWM has held these films forever, but is still adding them to a proper catalogue).
For what it's worth, here's the full list as copy/pasted by my bleary-eyed self. You can filter in Excel for pilot, date, squadron etc.
View attachment IWM Guncam Clips.zip
The file does not contain the IWM's "Catalogue Number" reference for the films which contain the individual clips. All the same, if you're looking for a particular pilot, or squadron or date, go here:
Imperial War Museums
type "camera gun footage" and the pilot (or date, or squadron, etc.) into the search box, and some results will pop up. Each item which pops up has a separate catalogue number, within which many (sometimes hundreds) of individual clips are listed.
NOTA BENE - none of these clips is available online. I believe they can be viewed in person at the IWM, though I imagine you'd need to make arrangements well ahead of time.
As I say, for what it's worth.