also via MAD - Iberia & LAN-Chile have flights that depart around midnight - the LAN flight comes in from Frankfurt - and arrive Santiago around 10:00 am
Much of a muchness in business cabin service (quite good) but LAN are sometimes a bit cheaper
Try and avoid going via LHR - BA/Iberia will book you on a connecting flight at around 15:00 which gives you several hours to kill in the vast Iberia lounge in T4S when you could easily leave at lest one flight later