The Greatest General 390BC-14AD

[Gaius Sempronius Gracchus]

Have you read John Creighton's "Coins and Power in Iron Age Britain" (2000) by any chance? He comes to similar conclusions about Commios transfer to Britain. Worth a look, very interesting theories.

No I haven't read it. But I shall certainly add it to my (ever-growing) list of books to source. Cheers.

I should add that it makes sense, to me, that doing such would be deemed a good Roman strategy. Having come to terms with Cassivellaunus and (one presumes) separately with the Trinobantes (whom Caesar seems to have had some relationship with prior to his 'invasions'), inserting an extra polity into the the Southern British 'pot' would keep them all at loggerheads with each other; especially if he doubted the strength of the Trinobantes (he claims, after all, that they requested his aid against the Catuvellauni (presumably)).
It is, I believe, the same principle by which the Arverni were allowed their independence - to stop one political centre from gaining suzerainty. I think he appreciated Commios' political and military skills and would have had greater trust in those to hold back the Catuvellauni than the Trinobantes on their own. This says a deal, I think, about his appreciation of both Commios and Cassivellaunus.