Hello haze73
Don't think it can be 24th Foot, I believe they wore a Sphinx as collar badge, whereas this chappie is wearing grenades. Grenades were worn by Artillery, Engineers, some Guards and I believe some Fusiliers. At present Gunners have 7 flames and Sappers 9, but I know this has varied over time.
As macintosh says there was a large barracks in Gravesend, and a fort which would have been garrisoned by Royal Artillery - there are numerous articles on the Tilbury and Gravesend fortifications.
I always knew the collar badge as a collar dog, and the grenade as a bomb, but perhaps this was just an oddity of the unit in which I served.
Coelmar