How to repressurise a Baxi Duo Tec Combi 24 HE boiler
Looks the same as mine, and since I've ended up here with the same question, I thought I'd update with an answer.

Looking at the third photo it looks as though you have the filling loop permanently fitted (as I do), with the two end caps hanging down. On the videos I've seen on Youtube and the Baxi website the taps are black and round, but yours is the same as mine with the two blue lever style ones, so...

From what I've read you need to turn the boiler off, so I did, then open the blue tap on the left fully. Then slowly open the blue tap on the right and watch the pressure gauge. You should get into the green section, around 1 to 1.5 bar. Then close the right tap first and the left tap second.

I'll finish off by stating that I'm not a plumber, but this is what I did and it worked for me.