Helen, in the 1960’s I was registered by the British Kennel Club so believe I have some knowledge of our canine friends. Your little dog does not need to go for walkies on beaches. Indeed, it is a bad place for them. Sand gets between their pads & causes intense irritation, peebles can be sharp & cut the pads, seawater is very bad for their coats. Perhaps you let him race around off the lead, just imagine the horror to other people if I let off my 4 German Shepherds. Spain used to have all dog free beaches until the British wore them down & they gave in.
Do dog owners imagine the tide will wash away any poo their pet deposits or even think that a small child may well build a sand castle from sand containing urine? Your pet will be quite happy to be taken for a nice walk on a lead around streets & be able to be properly disciplined whilst doing so. I live further north than you & find the Dutch, Germans & Scandinavians who have used my Kennels, mostly agree that beaches should have remained dog free & indeed I believe are happy to spend their euros in Spain also.