Sophie, there seem to be gillette-type razors for ladies from the 1920's onwards - but they were far from being mass market. My mother and her generation of northern working class women born in the 1920's seemed to regard anything to do with hair removal or hair colouring as secretive and vaguely sinful. So while I knew she would nick a razor blade from my dad's supply and whisk off underarm hair if she had a sleeveless frock to wear, she never did legs (legs always in thick stockings or tights) or plucked eyebrows, and like all my aunties lied through teeth about dyeing her hair when it started to go grey. I wonder if this was a hangover from a previous era - ie a woman showing off her legs / body would be an 'actress' ie prostitute. I recall my mother's deep disapproval for example of a young neighbours bleach-blonde beehive do - or even of my plucking out the middle bit of my monobrow!
In addition, the local nature of shopping meant everybody knew within hours what you were buying - asking for something off-beat at 'Timothy White's The Chemist' would spread like wildfire........post-war austerity as well as rationing may have had an impact, as well as colder houses and some very cold winters after 1945 - if your legs aren't out and about no point shaving them - and bathrooms were cold, hot water often in short supply - many houses still did not have indoor bathrooms, most people shared bedrooms - all of which made a head-to-toe body waxing less than easy to achieve.