I think you are right to keep him awake this winter, especially as he had that problem with his eye in August, and he is still so young.
The crispy florette salad is fine, but I wouldn't feed too much of it. It's mainly different lettuces (although there are some other things in there as well) and while lettuce has lots of water and helps with hydration, it's what we call a 'wet' food. These are foods that don't have a lot of fibre and go through the digestion system quickly (and tortoises are designed to digest food slowly). So some is OK, but don't make it a majority of the diet.
The edible pansies should be fine (but do wash them well in case the plants were sprayed with anything while growing). Even in winter there is usually something growing outdoors (plantain, low growing campanula, etc.). A little bit of kale is OK too -- but not too much, as it's a member of the cabbage family and they contain goitrogens so you don't want a lot of them.
For a commercial food the only one we would recommend is Testudo Pre Alpin, and it is excellent. It's composed completely of plants from alpine meadows and is high in fibre and low in protein, which is what Truck needs. You can buy it in several places -- here is one:
https://buzzardreptile.co.uk/?s=PRE+ALP ... pe=product It comes in 3 four varieties: original, herbs, fibre, and baby. Some are loose and some are in big pellets called cobs. You soak it in warm water and it rehydrates and expands, so you don't need a lot and it goes a long way. I would mix a bit of it in with your crispy florette (wet the florette leaves first so that the Pre Alpin sticks to it), and then gradually reduce the lettuce and increase that.
Here's an article on winter feeding:
http://www.tortoisetrust.org/enews/
The other thing you can do is buy special seed mixtures for tortoises and grow them in a succession of little trays that you can put in with Truck when the plants are big enough to eat. Shelled Warriors sell seed mixtures, and I would buy the smallest quantity of, say, 10g of the mixture with 10 varieties, or 5g of the luxury mixture with 65 varieties (you need to scroll down the page to see all the varieties), and try and grow your own to supplement what you are giving him:
https://www.shelledwarriorsshop.co.uk/s ... s-54-c.asp
I hope that gives you some options,
Best,
Nina