James, re The Sweet, I have a handful of singles from their heyday - Blockbuster, Hell Raiser, Ballroom Blitz, Teenage Rampage, Fox On The Run, but it's so long since I played them I can't even remember what's on the b-sides
You are right though, they always wanted to be a success as a songwriting outfit in their own right. In fact I think they split with ChinniChap and released the self-penned
Love Is Like Oxygen which IIRC did okay-ish, but I don't think they had much commercial singles success after that.