A guided tour of Prague transports Alastair Gilmour through flower power to food and beer heaven. Here in a historic part of one of Europe’s most beautiful cities I’m about to commit a crime. I have an aerosol paint can in my hand and I’m going to “tag” the wall in Grand Priory Square in Prague that belongs to The Sovereign Military Order of Malta. Nervously, I scrawl “Nice Wall” and step back to admire my burst of creativity. It’s OK, though. We’re at the John Lennon Peace W