Light mount looks like the one that comes standard with the pelago commuter racks and rasket.
how have you secured the dynamo cable under TT?
DI2 Wire Cover - https://bike.shimano.com/en-EU/product/component/duraace-r9150-di2/SM-EWC2.html
Treated the underside with a Fairy Liquid bath, then many rinses. Dried with a hairdryer, then used isopropyl alcohol and then the merest kiss from some nail polish remover. Heated the area with the hairdryer and then stuck on.
This method seems to have worked well with my Brother, but it hasn't been tested on a long tour yet - at £10 a pop several of the sticker things, I don't mind replacing them.