LATAM has a European sale, to GRU from £1494, from LHR, other destinations available (eg LIM, from £1550 via GRU). Should be able to route via MAD/BCN for no additional cost for an extra 40TP. Book by July 4; outbound needs to be done by 31 August (departure from August) but 1 year return window. Availability seems somewhat limited.