I'll start the ball rolling by saying it is late 20's, possibly very early 30's as acetylene lights & hand change were rapidly on the way out by 1933-34.
Once Velocette introduced the foot change in the late 20's the majority of enthusiasts couldn't get it quick enough. Try working a handchange on a rough road with girder forks bouncing away in front of you and the advantage of footchange are very obvious.
Same with acetylene lights. Electric lights were readily available on expensive bikes or on a cheap Villiers powered lightweight. The price of electric lighting was dropping fast in the early 30's and few riders would choose acetylene lighting over electric.
You might have acetylene lights on your sports racer but that bike is a touring machine, not a sporting one.
I would definitely place the bike as late vintage, early post vintage.
Cheers, Bob