On 24 July 1889, Henry Edzell Morgan Lindsay (1857-1935) married Katherine Ellen Thomas (1886-1937), the latter being one of the heirs to the Llanbradach Estate which had been in the Thomas family since at least the early 16th century. They had four sons and two daughter. Three of their sons died in the Great War. All three are named on the Ystrad Mynach and Hengoed Memorial and also on a memorial on the wall of Church of St. John The Divine, Cwmbach Llechryd, Radnorshire, a church built at the expense Miss Clara Thomas of Pencerrig on land that had come to the Thomas family through marriage.
  George Walter Thomas Lindsay, born in 1891, was their eldest son. He served from the start of the war. He was Lieutenant when, wounded by snipers near Ypres, he was hospitalised in St. Thomas’s, London, but later returned to service.
  He died when as Captain of Royal Field Artillery and attached to Royal Flying Corps (R.F.C.), he was killed in a flying accident, as was his First Air mechanic, when their aeroplane fell from a considerable height into a field near Bristol. A report on the inquest in Gloucestershire Chronicle included this evidence from Lieutenant Kerridge of R.F.C.:
    on Tuesday evening, about 5 o’clock, he [Kerridge] saw the deceased officer in the air. He was flying level in an easterly direction, and was between 2,000 and 2,500 feet up. Deceased seemed suddenly, however, to put a steep bank to the left on the machine, and started a rather steep spiral. After about the first turn of the spiral, witness noticed that the tail plane was not in the same horizontal position as the main plane. Then the pilot seemed to try and get out of the spiral, and while doing so the tail plane appeared to rock up and down laterally, during which time deceased was flying more or less level having got out of the spiral. Then the tail plane turned, and the machine very soon got into a steep spiral, which developed into a spinning nose dive. By that time the pilot had lost all control. The machine fell a considerable distance, gradually turning upside down. It came out of the upside down position, and fell more or less vertically. About 200 or 300 feet before it reached the ground it again turned upside down, and struck the ground in that position.
When asked what he thought caused the accident, the witness replied I think that either previous to when I saw him or just before the pilot started the spiral there had been some fracture of the longerons in front of the tail plane. Other military personnel confirmed there was no problem when flying the machine immediately prior to this incident nor when the frame of the machine had been tested independently of the engines the previous Sunday.
see Gelligaer Journal Volume 25 (2018) pages 77-82