Sorry for replying to myself here, but now I'm properly worried that my seemingly legal connection may be broken. Looking at the MCT for GRU Domestic - International G3 to LH I see the following:
STANDARD.D/D...D/I...I/D...I/I.
ONLINE 1.00 1.00 1.30 1.00
OFFLINE 1.00 1.00 1.30 1.00
** OR * ARE ALL
G3-** DI 2.00 TRM 2 - 1
G3-** DI 1.30 TRM 2 - 2
Perhaps someone who has more experience than me at this can correct me, but to me it seems like my connection is legal because it defaults to the 1 hour rule, but if it had been a T2 - T1 connection or even within T2 it would have been an illegal connection. Can it be possible that the MCT is just not updated with T3 in mind?