I thought that too but the loaf rose well - don't know if there's enough food for the yeast in the Splenda or if its something to do with the gluten or eggs but it works a treat!
I don't use sugar when handbaking bread, a longish slow rise time allows yeast to get what it needs by converting the carbs in the flour. I did put sugar in the breadmaker when I used one though, as that does not allow sufficient time for the natural process of extraction to occur
Lidl do two bread mixes which can be made in a breadmaker, Countrystyle Wheat-Rye Wholemeal Bread and Wheat-Rye Bread. Both of these work for me, though I prefer to do it manually and give it a longer proving time.
The difference between the two is that the latter uses a slightly higher wheat flour content than the former. However, both are wholemeal wheat flours and both include dried sourdough.
The countrystyle loaf uses a different type of wheat flour to mix with the rye flour, a type known as 1600 which results in a typical 'black bread' look.
But is still a springy loaf and not as solid as pumpernickel. It's very nice if you mix in caraway seeds or cover the outside with onion seed. Bit of cream cheese and a slice of smoked salmon with some dill, bloomin marvelous!