Honestly, nothing wrong with plainest of the plain supermarket fondant.
The small amount of additions to make it pliable and easily rolled (for cakes) won't harm the bees. Many of the 'additives' used are similar to the minor constituents of pollen (veg oil for example).
Thus its a reasonable choice for a small quantity with immediate availability.
Accordingly, its often used in mini-mating-nuc feeding by people of the eminence of Terry Clare.
However, between now and the start of a decent Spring nectar flow, even a single hive could get through more than 5kg. And 5kg from the supermarket is going to be about the same cost as 12.5kg of Bako - so, *IF* you have one or more hives *needing* feeding at this point, Bakers fondant makes sense.
The downside of under-feeding (death by starvation) is a whole lot worse than the downside of over-feeding, so its right to err on the side of excess if you have any doubts.
Tightly wrapped, Bako stores from one year to the next, so it isn't a waste to have some in store.
We were getting it from Bako for £11.00 a box this winter
