Gav, maybe not so popular now, (Leeds are not the attraction they used to be), but I was aware of it during 70's/80's/90's .... Leeds seemed to have a large following amongst Motherwell fans, much more so than Man-U or Liverpool back then. I used to travel down regularly with the Motherwell Whites.
Not sure about others but for me, my 1st exposure to the English game from what I can remember was the 1970 FA Cup Final (in those days that was the live game on tv, not the Scottish cup final taking place on same day). Anyway, Leeds seemed to be portrayed as underdogs and this young lad kinda liked the white strip with the sock flashes and my realisation that they had a very strong Scottish influence cemented my attraction. Bremner, Lorimer, Harvie, Gray, Jordan, McQueen, Gray jnr, Stewart, etc., and the rest is history.