Binchester in Britannia

The inscription from Binchester (mentioned once or twice before) is now published in Britannia 43 (2012), 399 No. 6.

I see the reading sacel(lum) has disappeared and we're back to sacer (which is what it looked like to me all along). I'm not sure about Tertullo e]t Sacer(dote) cos; even if the consular date of 158 is attractive, the preceding fragment doesn't look like the bottom of a T to me. But it is hard to find another context in Imperial nomenclature or the name of the relevant unit (which ought to precede the formulation cui praest...praefectus equitum). We might go for Elagabalus, who was styled sacerdos amplissimus dei invicti solis, but the only example of this from Britain (RIB1465 from Chesters) is a restoration of a mutilated (post damnatio) text. The fragmentary RIB 1915 from Birdoswald contained another possible sace]rdo but is now even more fragmentary than when initially recorded and little help.