Qantas flight seat selection booked as a LATAM codeshare

[scottz95]

Hi all, I booked a trip to Peru next year through Flight Centre earlier this week. It's in J but they've ticketed two of the Qantas segments (PER-SYD, SYD-SCL) as Latam codeshare flights.

Unfortunately I can't seat select for these flights through either Latam website nor the Qantas site with the details I have on my ticket. Does anyone have any experience in trying to get seat selection to work? Any help would be greatly advised.