Depends where you look. I'd consider Dacourt a 00/01 signing as it wasn't agreed until May of 2000, which to me, makes him an 00/01 signing as he didn't play for them until that season. Same thing for Robbie Keane who signed in the April of 00/01 after being on loan at Leeds from December, the permanent transfer went through for the 01/02 season. Also, Keane permanently signed 5 months after Ferdinand who agreed to join Leeds in November and made his debut in December, so Ferdinand was their first £10m+ player.
That's fair re playing dates. I was simply continuing the original convo about when money was spent (90's). But accept it's a little grey as to where you'd count em.