That is a cracking photo and your Grandfather looks to be a splendidly dapper gentleman - shiny shoes, pinstripe 3 piece, bow tie and trilby. It's such a shame hats have gone out of fashion. Grandma suitably attired and, as you say, not wishing to appear uncouth and maintaining her modesty by riding side saddle.
Dunno what it is about race sidecars but their build fascinates me - CTL Company again. Lovely bit of welding on that (substantial) headstock. It had two calipers on the LHS and only one on the RHS To counteract a sidecar's tendency to turn left when braking perhaps? Rear end with a short swingarm (UJ not in place) and what looks to be a tyre on the wrong way round.
My mother back in the 60's sat on Bob Rowbottams outfit at the TT. He was one of the many also rans making up the numbers
A reminder of some old images posted (Oh My God) 6 years ago: https://www.ducatiforum.co.uk/threads/timeline-my-parents-and-bikes.77332/
