Not that I can help much but it looks to me as if the car is one in a convoy of some sort, rather than a rally/race. I say this because of what looks like a temporary car number (G5x) fixed to the radiator (no permanent number would be placed there, I think, plus it does not look like a registration number) together with the passengers all being in some type of uniform. One way to approach the various answers that such a photograph may lead to is to show it to your local library, or else a newspaper editor/reporter because they will think of people/organisations who can shed some light on it. Another is to contact the AA or RAC, or better still some of the vintage car clubs/groups who will readily identify the type of car which then gives you a time frame (if you don't already have it). As for the uniforms, there are similar special interest/hobby groups/clubs/etc. who might be able to help there. If you don't know the location then finding that out is probably the most challenging part, although with perseverance even that might be possible, assuming the buildings visible in the photo still exist. Anything you know about the provenance of this picture will help, particularly on this last point.