Do tinned foods go off (stale)?
Assuming the can was canned properly and has not been damaged, the contents are effectively sterile, because the food is boiled in the can after it's sealed. There might be some degradation in texture and taste, but in terms of food safety, they are effectively safe.

Note that the date on your tin is given as Best Before, not Use By. That generally means it's safe to eat after the given date, but it won't be at its... best. Given that you're only 12 days out of August, and with the proviso of exercising due caution (don't eat them if they're green), you should be just fine.