Having been bitten in 2014 on the leg whilst cycling in calis (and not on the prom) I can confirm it happens and the hospital confirmed they treat people every day. As it drew blood it's was advised to have the rabbies and tetanus course!
A few years ago we were at the far end of the prom by the old Caretta Beach Bar, now the Aroma. We were walking past a quite large dog which was chained up and appeared to be asleep. We were a few yards away when it, quite suddenly, went for my husband and tried to sink it's teeth into the top of his leg. Fortunately it caught the pocket where he had his phone but went through the material and left a couple of dents in his phone case.
Now we never, ever approach dogs in the street especially when abroad so there was no provocation whatsoever on his part, just simply walking past it. So yes, it does happen!