What about the man with the big tie, third from the right, front row ?
Is that a sort of horseracing motif on it ?
The way they're dressed looks like some sort of works outing ? Maybe a day at the races ?
The building looks 1930's, but I'd say the photo is more 1970's.
Incidentally, Agfa Brovira paper was produced from the 1930's, but there was a lot of post-war surplus stock around in the 1950's and 60's. The paper is still made today, but it's now called Agfa Brovira Speed.