You also do not need to deselect EGNOS. The open service is still completely legal to use and that is what is required for LNAV/VNAV. You just switch to the higher LNAV/VNAV minima.
Thanks Gipsymagpie, however the Garmin G1000 doesn't allow you to choose which type of PBN approach you load. If it sees SBAS as active, you can load the LPV but not LNAV/VNAV, the latter can’t be seen as an available approach. The only way to see and load the LNAV/VNAV is to disable SBAS before you load the approach; SBAS can then be reselected leaving the LNAV/VNAV approach active.