I’m nearing the end of my 33 trips, the magic number I set myself in 2007. In that number, I decided, I would bag as many of Harry Bell’s sites as possible in an attempt to prove that the aligned sites of Glasgow and its environs hold the key to a secret geometry. My trusty OS maps – the Landranger 64 and the Explorer 342 – are a bit frayed at the edges. For the last ten days it…