Well at least you saw the Sun - total greyout here
It's quite common for the halo to be incomplete - to get a complete halo there needs to be the correct shape clear ice crystals over a wide area of the sky. Particularly when the sun is low, it's quite common to have the dogs but not the upper part of the arc, as shown in your photo.
There are segments of parhelic arc extending out from the dogs on both sides - more obvious on the right hand side - it's a pity the field of view isn't a bit wider so we could see how far they extended.
