Well, granite is an igneous rock with a phaneritic texture, meaning visible crystals. Gneiss on the other hand are metamorphic rocks that are banded; formed in layers caused by heat and pressure. That's the main, big difference between the two. Granitic gneiss is gneiss with a similar composition of granite (mainly quartz, feldspar, and biotite). It can have bands, but it is not truly a granitic rock, as it was not formed in the same manner. Gneissic granite is the same thing as granitic gneiss, just you swapped the words around.
The term banded refers to sedimentary or metamorphic rocks, where there's layers of different rock compositions. Due to how granite forms, there won't be layers, or bands.
I've never heard of a banded granite. Not technical terms anyways. My guess is that someone is referring to a gneiss. Some rock types are also mistakenly identified as granite too, like quartz syenite.