As I understand it needs you for RV. I found and saw only one mention in internet. I think you saw it too.
But I have some information from other resource. I saw few archaelogical finds from Lerida (Catalonia, Spain). One of them was a silver medallion with engravings "L. Aelius Longinus" on one side and image of horse's head on other side. The medallion was dated end2-beg3 AD. Condition of it was not so good and process of date was hard as I know. This was strange thing because had a little hole and most likely hanged upon Aelius's neck very long time ago. Looks like a modern badge from soldiery.
I may surmise only that Longinus was from Spain (probably he has a land near modern Lerida) and returned to home safely from Britain. I may surmise also he wasn't so reach because his medallion was made from silver and not gold. This is take place of course if Prefect of Cavalry and medallion's owner were same person.
Well I don't know how it may help you...