Hi, I'm also a chef, although I've worked in hotels mainly, but same sort of hours. I've found that I had to just go do it, which was hard because as a chef in a busy business you feel like you're letting your part of the team down by taking a couple of minutes to look after yourself. If you're a smoker then that's a perfect time to do a quick sugar check, and if you aren't then doing it when someone else is smoking can work too.
When it comes to service, if you know when your busy times are, then doing a check before it works well, I would useally aim to have my sugars at about 8-9 before service so that I wouldn't need to worry about them during.
If you have issues with your boss, as I did at one job, I found telling them that they could either let me take 2 minutes when I need to or they can ring an ambulance when I collapse, changes their mind!