From George Cohen's website:
George: "Circa 1925 Flat Tank Model 18. A very nice Flat Tank Norton. Taxed and tested and a solid runner. 19 inch wheels and Dell’Orto carb are the only significant deviations from factory spec. Machine is currently in south Wales. £17,000" SOLD
JdK: a nice flat tank Norton! Though one could have a lengthy discussion about which deviations from factory spec are significant or not.