Ello, I've just found this forum, what a result.

I've also found out that the music I really dig is sometimes called 'Modern Soul'!

Anyway, I've got an old tape with a song on it that I'd love to track down ... the chorus goes "I'm in love and don't know why" it's by a girl group and sounds a bit like Two Tons of Fun, Jocelyn Brown???

Sounds like it could be this one by Hodges, James, Smith & Crawford - "I'm in love" on Mpingo records:

https://youtu.be/hY6VMgC0_KY

A fine record! First listen for me, many thanks for the link John mate :-)