Low Bg

YES

When we have a hypo we need to treat it with fast acting carbs. Our bodies do not act well when our brain does not have enough glucose.
Fast acting glucose is something like jelly babies, a sugar drink (fruit juice, Lucozade), dextrose, ...
As a type 1 treated with insulin, a hypo (low BG) is a constant concern. I always carry GlucoTabs with me wherever I go.

Definitely YES. As @helensaramay has already said our brains require glucose to work. So something fast acting is a must.
Increased physical activity will lower your blood glucose anyway, so you will need an increase in carb intake just before your physical activity.
Congratulations on your weight loss AND on your physical activity, especially with 4 stents in

Definitely a "YES" to taking something other than redcurrants and cheese.

There's clearly an improved insulin response with increased walking for me, I do a similar amount of walking and really need to watch out for hypos if I've not allowed for the walking when I'm calculating my fast acting insulin dose.

So, I've always got dextro tablets on me, plus a can or two of full sugar Coke on a longer than an hour walk, and a box full of carby-snacks when out for the day. Oh, and a couple of frozen bottles of water, to keep me and the drinks all cool, which melt nicely across the day and give me a cold drink all through the walk. I look on that lot as weight training as well....