I’m glad I found this tread! I also have a Sentinel Kinetic MVHR installed and this has been on my list for a while. Just looking back at the manual and I too just found the bit about the BMS which I was otherwise not aware of. Please keep this tread up-to-date with what you find out from Vent Axia.
Just looking at the installation and servicing manual and on page 20, I see the wiring diagram which shows the BMS slot. If the BMS does not work out, wondering if we are able to do something in ESPHome to control it that way? I am new to ESPHome so we would definitely need more help.
(Not my photograph: Taken from here)