Spink's Anglo-Frisian Coin: When and Where was it Found?

Laughing and dancing
all the way to the bank.

On a metal detecting forum near you, member "Tommo" is happy: "My bro's Saxon gold he found today (auction update page 1)" First he boasts (Sun Sep 07, 2014 8:28 pm) to other members a "Nice little yellow found by my bro today, lucky sod". Then there is the update (18/12/14): "Although we don't like to sell our finds, due to agreements with organiser and farmer this one had to be sold. Sold at Spinks 20 minutes ago". So this was found at an organized artefact hunting meeting held by a detecting group "somewhere in West Lindsay" on 7th September this year. It is recorded in the PAS database LANCUM-9E265D. Just three weeks later, Saturday Sept 27, 2014, it was in Spink's the coin seller who supplied the ACCG with their paperless coins for their 2009 Baltimore stunt.

There however is a problem. The PAS record gives as the date of discovery "Thursday 7th August 2014" a full month earlier than the organized event at which it was supposed to have been found. Was this date arrived at from independent documentation of the circumstances by which the finder came into possession of another's property? By what means do the PAS ascertain the veracity of the information supplied by the finder and check it against other sources to prevent false data entering the database?

In fact the Spink's catalogue entry (Lot: 484) gives the same earlier date of finding, presumably obtained from the consigner: "Found West Lindsey district, Lincolnshire, 7 August 2014". Presumably Spink's verify the provenance details of the antiquities they offer very carefully.

So was this coin really found at the metal detecting group 'dig' of 7th September, or was it in fact found earlier, perhaps even on a different landowner's property? Why is there this discrepancy between three different sources? How reliable are the "data" in the hastily-compiled PAS "database" of finds made by metal detecting collectors for personal entertainment and profit? What knowledge went missing with the sale of this object?

UPDATE 22.12.14
 "Apparently 2 bidders were fighting it out. One from America and one from France. It's now back in France were it was probably minted originally." errr... "Anglo-Frisian"?