I think it's a 1950's romper suit
I've still got mine along with my kipper tie and flares
Yes it was a gentler (and less PC) time Chris, halcyon days, "Oh those lazy, crazy, hazy days of summer....."
Edit, I loved the Wooden Tops they don't make 'em like that any more!!!
I remember "Listen with mother" rather than "watch with mother" ?