Tyre puncture fixed at tyre dealer few days ago. Balance was done and now all tyres sit around the 42psi mark. When driving they climb to 45-46psi. Should I be concerned? The door plate recommends 35psi, however I usually have them at 38psi.
This is too simple , just let air out and use a tire gauge to get them to what the door plaque says.
Completely normal. Driving heats up the tire. Hotter air expands to create higher pressure.
Let some air out. 42 psi is too high if the door card says 35 psi. 38 is OK, 42 is a bit too high.
If you want the best balance of traction, even wear, fuel economy, and comfort, use the recommended pressure.