Aerohack. MANY thanks. No need to apologise for not mentioning my grandfather's company. I deliberately said nothing in my first post!
Well, yes, I have some stories from him, via my father. These were part of one chapter of my father's memoir that was published a few years ago. I assisted my father with the manuscript and so have the original, prior to editing. My grandfather was intimately involved in the flying scene. He was a good friend of 'Smithy', who used to keep his aircraft in my grandfather's hangar.
Also, to quote my own father, "Probably my Father's greatest friend was Leslie Irvin, the American parachute designer who had come over to England ..."
When we lived in Cambridge (1959~1966) we were regulars at Old Warden but I have only visited once or twice in my adult years. Although I did accompany my father for a visit there in the late 1980s. My father gave some of his photographs and things to Old Warden.
... E.O. Tips flying the prototype Tipsy B at Heathrow in May 1937. He's making a very steep turn around a group of spectators that I imagine included your grandfather, and no more than a couple of feet above their heads. Your grandfather flew one of a formation of three Tipsy Bs during the Royal Aeronautical Society's garden party at Heathrow the following year.
I think that this was adjacent to Heathrow? I have just moved flat and the book that details this is still in a box. The air display that, I think, you refer to, is mentioned in: Heathrow: 2000 Years of History by Philip Sherwood?
The field to the south of Hatton Cross was used as Heathrow had not yet been laid out. That happened only in the war???
The field was at the back of the Fairy Aircraft Factory and had another name starting with 'H' but not Hendon! The Fairy Factory is, of course, now Lufthansa Sky Chefs! My father worked at the factory at the start of the second war, before joining up for the RAF on his 18th birthday.