I am very happy with my bike, but it has developed a creak when pedalling.

I rode it for a week with no problems in the UK where I live and then took it to Tenerife for 6 days of riding. First day it was okay but on the second when I stood on the pedals it started making a creaking/click sound with each pedal stroke. I’m running Shimano 105 Di2 with a ZTTO T47i bottom bracket which I installed with the supplied tool with no grease or retaining compound on the threads. Crank spindle is greased and preloaded, as well as the pedals. I checked the chainring bolts and left crank arm bolts and those are torqued up.
Later at the hotel I managed to recreate the noise by pushing either side of the bike near the BB area with my hands. The noise usually only occurs once the opposite side has been pushed I.e. pushing twice doesn’t make noise twice, only when the frame is pushed from the other side again.

I carefully inspected the frame for cracks around the BB, chainstays, down tube, reinstalled the handlebars and both bottle cages and the noise persists. The frame looks pristine on the outside. I am running a transparent black glossy finish.

I continued riding it through the holiday and took it up some very steep climbs (eg tierra del trigo with 25% ramps) and nothing bad happened and no noise happens when not pedalling. I am a light rider at 57kg and not much power output, but the noise sometimes also happens when pedalling at 150W.

I will try and reassemble the bottom bracket but if someone has any suggestions they would be greatly appreciated.

Also, since I’m riding a small frame, the seat tube bottle cage bolts are too high, which makes it impossible to take a 750ml bottle. Are there any solutions to lower the bottle cage mounts?

Can you tell me about the headset on your build?  What c ring did you use with the bearings and headset ?