Handley Page Harrows.
Geriaviator,
Once again, thank you for the interesting pics. It is sobering to think that that same summer two sixteen year olds (a cousin and I), propped on our bikes, were looking longingly over the fence at aircraft flying from Wyton.
Looked up the "Harrow"; Wiki led me to the Long Aerial Mine - a hare-brained idea if ever I heard one - of which I knew absolutely nothing. Worth a look.
Danny.