I am planning to fly on two separate tickets as follows

Lan Ecuador

SCL - EZE in economy depart scl at 7am arrive 10:05

Depart

EZE - LHR at 12:15 in Business on British Airways

Firstly will Lan check the bags through for us I assume they would, and therefore could we just transit in Buenos Aires and not clear customs

Second is this enough time I figure it is fairly safe as we could always catch the one at 7:35am if the first one is canceled late etc getting us into eze at 10:35

Third would Lan charge us excess luggage even though we are connecting onto a business class flight with three bags allowance but I assume we would be over the tickets 23kg limit, anyone had any experience with this? I am really just asking out of hope. also I am one world Sapphire if that means anything


thank you for all you help