Yes. Tesco, Sainsbury's, ASDA and Polish supermarkets
See Mysupermarket info: Lowicz Raspberry Syrup
Brewing up a Belgian
Re: Odp: Brewing up a Belgian
People here usually add some kind of artificial sweetener (Lidl's Cologran seems most popular) when brewing with such syrups. They're all high in fermentable sugar, making beer very dry. You might want additionally mash higher, 68-69c, to compensate high fermentability of these syrups.