Regarding the Failure of the Herrera deal -
Radio 5 Live - it was down to beurocratic reasons. Apparently buy out clauses involve giving the player the cash so they can buy out of the contracts with their club. This can throw up tax issues if it is seen as an income for the player by the Spanish tax man. Basically they seem to have the cash but its a huge ball ache to sort out, and with a couple of hours left was a non starter.