GB KING GEORGE V 1929, PRICELESS ERROR, 1½d PURPLE-BROWN Mi172X, SG436, MNH

Stamp of King George V in denomination for 1½d(British Penny-old) with quite a few errors however the one which is circled with red colour (See images) is very-very rare ERROR - DOUBLE BROKEN FRAME, which unfortunately is still NON-EXISTENT VARIETY by SG, as we cannot find this unique and very big error listed by SG. The only trace of this error could be find in Special Booklet for GB stamps written by private collector 1978 in Zurich, Switzerland(Please see image with the error in red circle). Stamp exceptionally well perforated and centred. By the same author the price for such error would be very high. There are also few other errors - see image. Stamp in very nice overall condition and could be part of any collection even more demanded collection. Calculating the price for such error from 1978 to the equivalent value today, stamp would be valued in region of £1,088.00+ or as the author of this booklet wrote: This error is priceless and need to be part of any serious collection of GB stamps errors!"