With regards to the pendant made of a Byznatine coin found in England, I thought it would be interesting to note that copying Islamic coinage was also in vogue.\
http://www.caitlingreen.org/2015/03/some-imitation-islamic-coins.html
These include:
An eighth-century coin of Offa, Anglo-Saxon king of Mercia, based on a gold dinar of the 'Abbāsid caliph Al-Mansur struck in AD 773/4
An eighth-century imitation of an 'Abbāsid dinar of AD 773/4, thought to be minted in Carolingian Europe by Charlemagne.
An imitation of an 'Abbāsid gold dinar of 789–90/792–3 with added crosses, thought to have been struck in Anglo-Saxon England, perhaps either by Offa or Coenwulf of Mercia
A 'Christian falcon' imitation dirham issued by the Kievan Rus' in c. 950, reused twice as a pendant and found in Estonia
A Khazar "Moses" dirham, minted in 837/8 and found in a hoard on the Baltic island of Gotland
A late ninth- or very early tenth-century Khazar imitation dirham, with the outer edge legend transformed into tamgha-like signs; an example was found near to Acklam, North Yorkshire, and appears to have been reused as a Viking brooch-fitting
A tenth-century tari of Gisulfo I of Salerno, imitating a Fatimid quarter dinar
As the British Museum points out, it is unlikely that these would be minted on the basis of their Arabic inscriptions, as a legend reading "there is no God but Allah alone" would seem inappropriate for coins sent to the Papacy. Judging by the Kievan Rus coin's subsequent use as a pendant, in addition to the imitation Byzantine coin used in this fashion, it would seem that these 'imitation' coins were produced because people - particularly the still-predominantly-functionally-illiterate kings who would have ordered them made - liked what they thought was the pretty decoration, as did their subjects.
I suspect it's more than "pretty"; rather, this is what people expected a gold coin to look like. Perhaps there was even a hope that people would see the similarity to the Arab coins as a promise of the same gold content and value.
Good point: if they had assumed the status of trusted standard values (like the old Attic drachma), then imitation is the sincerest form of flattery and of qualifying for a common standard.
Roman and Greek coins were imitated (by 'barbarians') well before these dates.
David B
As was the gold stater of Philip II in pre-Roman Britannia, the one potential supporting datum for the idea that Alexander visited the British Isles during his exile. (There are two, if one believes Alexander named Scotland - scotia, darkness, suggesting an arrival late in the year.)