SG815f 5d Cottages MISSING GREEN The UNQIUE Cylinder PAIR U/M

1970 British Rural Architecture 5d. vertical strip with sheet margin at left showing plate numbers both stamps showing variety Green omitted (cobblestones) also showing green (cylinder IF) omitted in margin unmounted mint and believed to be unique. a most important modern error. R.P.S. Certificate (2008). S.G. 815f unpriced. (Most of the major missing colours are no longer priced in SG) These are priced in Stoneham 15th Edition (C270g) at 30000++ pounds