Adjusting the pressurestat on an Izzo Vivi or Alex
Pressure adjustment on the Vivi or Alex is very easy and the pressurestat (a MA-TER XP110) is not overly sensitive.
The pictures below (red dot and arrow added for clarity), show the position of the pressurestat adjustment screw when adjusted from 1.5 bar to a lower 1.1 bar average. It was adjusted simply using an electrically insulated screwdriver. Always have the machine switched off when doing this adjustment and allow around 6-8 boiler cycles for things to settle, before adjusting again. Simply click the images below for larger versions.

In a Vivi (4 screws need to be removed and the access plate under the cup warming tray just lifts off), there is an access hole but it's in the wrong place.
For an Alex (MK1, not sure about the MKII), simply lift the cup tray and the pressurestat can be seen and adjusted via an access hole near the front left of the machine.