Im in the same thinking as DinQ. We have an agrreement allowing limited personal use of field service van. But being up front i said from the start. I keep the van under cover and wash the vehicle in my own time, and im happy to do that as long as i dont get questioned about doing my shopping , or running the kids to w/end sport or something. As for start times ill generally take off how long it takes to get to work from my travel time if starting on site. And adding return to workshop time when going home from site.