Any question answered...

I noticed that something near my bottom bracket/chainset is making a creaking noise when I apply above-average force when pedalling, particularly at starts and climbs.
I've tightened the cranks to bb, and chainring bolts are solid.
All parts are new so I suspect that my bb might just need tightening, am I on the right track?

Remember noises from anywhere on the bike often manifest themselves at the drive. I had one once that turned out to be a cracked seatpost bolt.
Check this thread?