The letters GRVI, likely commemorating King George IV, is visible in aerial photography as early as the 1940s (RAF AP 106G/UK/1471 Frame 3361), possibly dating from 1936 coronation of George IV. The letters are visible in an Ordnance Survey aerial photograph of 1976 (76 041, Frame 027), in which they appear as clearings in the forest. Later aerial photography, notably National Assembly Wales photography from 2014, shows the letters as comprised of brighter coloured foliage than the surrounding trees, although the letters are not visible in National Assembly Wales aerial photography from 2006 or 2010. The letters are approximately 70-72m tall, with the inscription stretching across approximately 207m.

A.N. Coward, RCAHMW, 28.10.2019