Dealer with Close Links with the Council for British Archaeology Sells Silver Artefact

Dealer 'denant'  (Den of Antiquity Int Ltd  - Simon Shipp, Cambridge CB25 9WJ United Kingdom ) flogging off a (one presumes, disclaimed - but why not say so?) Treasure item for GBP 1,250.00

ANGLO-SAXON SILVER HOOKED TAG WITH A QUADRUPED DESIGN AND NIELLO INLAY
Description:
Date: C. 10th century
Information: A fine example of a silver hooked tag with two pierced lobe attachment points, and depicting a quadruped to central panel with an interlaced ribbon design and niello inlay. Condition: Hook a little bent otherwise intact and of a good size with excellent detail. Size: 23mm x 28mm Please note:- Any questions regarding this object/s will be answered ASAP during office hours 09.00-17.00 GMT Monday to Friday, excluding national holidays/bank holidays. Thank you.

How about just putting the information there upfront, without anyone having to ask a dealer openly flogging off such a thing? Where was it found? When? What was its Treasure Case number and when was it disclaimed? What is its number in PAS database, I could not find it mentioned there. It also says in the sales offer:

Items offered by denant (Den of Antiquity Int Ltd) are unconditionally guaranteed to be authentic. Certificate of Authenticity, Invoice upon request. Antiquities Dealers Association and British Numismatics Trade Association member and as such abide by their code of conduct. The BNTA has become an effective force in the fight against forgery, theft and other criminal activities, thus establishing a benchmark for the highest ethical standards in the domestic coin trade. Members receive early warning notices of counterfeit coins and stolen property. ADA’s Code of Conduct binds its members to ensure that to the best of their knowledge and belief all objects sold are genuine and as described. The Association is a Corporate Member of the Museums Association, is represented on the executive of the British Art Market Federation and has close links with the Council for British Archaeology.

But as such, what assurance is conspicuously absent in the above? May well be authentic, but is that the only measure of legitimacy in the UK antiquities market?