Sorry but the malted one isn't a HEB at all so you would need to syn it all. It's not wholemeal, just white bread with malted flakes in it. I wouldn't worry too much about it, just draw a line and move on.
Have you tried the WW thick wholemeal? You can have two slices of that as a HEB and it's more substantial than the other slimming breads. Or two slices of a small ordinary loaf like Hovis?