I previously owned a Honda Jazz hybrid and on the relevant forum there was a long thread on 12V batteries. Owners who left them three weeks or more could find problems when they returned to their cars. What I don’t believe has been mentioned so far is that the 12V battery on a hybrid is smaller both physically and in electrical capacity than a typical petrol car as the lithium traction battery does most of the work. So, any hybrid needs ideally to be used every couple of weeks to avoid a flat 12V battery. Even when not in use there is a slight drain on the battery from the alarm and other systems.
The LBX is a very nice car, you were unfortunate with the dead 12V battery but once replaced the car should be fine so it would be a shame to reject it.