That's a Funny State to be in! How Did That Happen?

 

                                 What a funny state                                         

I kept mulling over the state of preservation of the artefact recently acquired from a metal detectorist that had been authenticated by being passed through the Portable Antiquities Scheme "database" (including a lengthy writing up by Lisa Brundle of the BM-run Scheme's staff. As media reports noted at the time of discovery it was well-preserved and had its pin intact (rare on fibulae recovered from ploughsoil). I was looking through some auction sales and something kept coming back to my mind...

This fibula was ostensibly found at a commercial rally (Detecting for Veterans CIC) at Leasingham in the North Kesteven district of Lincolnshire. Its on limestone. 

The problem is the patina. It is very similar to some auctionhouse items with no documentation. There is a thin dark and very glossy patina with the brassy metal poking through (no visible cuprite layer), the metal under it is barely pitted. The gloss has a silvery-grey toning. Where there are grooves in the object some powdwery corrosion still adhere (has been left still adhering) to the metal, highlighting the relief. It looks as if it was left by cleaning off a similar deposit from other areas. But then, what did this object look like when it was 'erdefrisch' (fresh from the earth)? Because this is not the kind of patina one would exprect, even from the most basic of British soils. A selection of Roman bronze objects metal detected at Leasingham and recorded in the PAS "database" make the point:

Not only do the typical objects from the region look nothing like the 'patina' of the Leasingham horse, it does not look to me as if they could be cleaned to anything like that. 

But what this does look like is the typical 'patina' applied to modern Bulgarian fakes on the market of the 1990s. 

Is it possible somebody has been playing a joke on the finder? Or that a rally was 'seeded' with objects bought on the market to make detecting with this commercial firm more attractive? Such practices are rumoured, and there seems to be potential evidence for it from other 'Balkan' finds that turn up on them from time to time. 

Since the fibula has only continental parallels, and most of those are unpapered, I would like to ask the FLO who accepted this find to what lengths they went to verify the provenance of this item and its authenticity.