
Yes they do, just labelled "Giant House Rabbits". No mention of breed or the fact that being giants they do have a shorter lifespan than average-sized rabbits. If they have been poorly bred then that could be a lot less.
The pure breeds of Giants in the UK today are British Giant, Continental Giant (known as Flemish Giant outside the UK) and the [UK] Flemish Giant (the only Giant we had here in the last century due to quarantine rules about importing, so they branched off into a separate breed in their own right).
French Lops are now considered Giant as well, but were nowhere near as big 30 years ago.
Belgian Hares are not considered Giants although they are on the large side... but racy with it... more tall and long (like a greyhound). They are also considered to be one of the most intelligent breeds (along with Tri Dutch!).
Thinking about a recent discussion here about giant breeds of dogs having shorter lifespans due to size - it is true in rabbits so I am not surprised if it is the same in dogs.