I am the grandson you refer to as being fortunate enough to inherit Llanfendigaid. An exceptionally beautiful place it is too. See www.llanfendigaid.co.uk.
By the way, in the interests of complete accuracy, it is probably worth correcting a couple of points. My grandfather was actually born in Wandsworth, South London although he was brought up at Maesyneuadd. He left the Army as a Major and was subsequently promoted to Lt Colonel after being asked to take on the local unit in Wales as a "territorial"or the then equivalent. He shared a godfather, a Colonel Spilling, with the son of the famous founder of the Scout Movement, Lord Baden-Powell. He told me that he received the lion's share of the Spilling inheritance because old Col Spilling reckoned that the Baden-Powells had enough already!
He was a good Grandfather to me and taught me a great deal about the family history in Wales. We all encouraged him to document his knowledge, but he never did and I am sure that quite a bit went with him. However, he did leave lots of older documentation which I keep carefully. He also taught me about field sports and golf. Don't do that much of the former these days, but keep up the latter - even to the extent of restoring a historic golf course in Livingstone, Zambia which was founded only a year after he was born.
He would be 100 this year were he still alive - his wife Marjorie survives him and still lives in Cornwall. Her memories of Horsham are, I think, as fresh as ever.