ECU Tuning 2018 Ford Transit connect

[LOW BOOST]

Hi there guys,
I'm new to the forum.
I recently purchased a 2018 Ford transit connect 1.5 tdci LWB for business.
Was looking for some extra power and decided to an ecu software upgrade.
After the tuner did the software i could not feel any power difference. Maybe a slight difference if i really pushed it hard. But nothing evident.
Gains promised where 25hp and 60nm torque.
Regrettably we didn't do a before and after dyno.
My question is:
1) What is the stock boost levels for this model?
2) What can we safely boost up to?
3) what other mods can i do to safely increase power figures?

Regards from Durban South Africa.