But he's not asking about DRIVING ... he's principally asking about CROSSING BORDERS with a local bike holding a UK license.

And ... as already confirmed ... it's no worries if the TITLE of the bike
(Called LOG BOOK IN UK) is in the keepers name then all good. Aduana won't much care about your driving license ... it's your PASSPORT they want to see.
But if the title is in your name, all OK.

Insurance is ALL bought local, country by country. AFAIK, there is NO insurance cover that is valid in ALL countries. And ... as pointed out (proving you haven't searched much at all) ... there is NO CARNET in any S. American country.

The trick in all this is getting the Title for your bike in timely and affordable manner. Easier said than done and varies country to country.

You can also buy from another traveler and get the bike transferred into your name. (most US states this is possible ... if seller helps out)

Lots of possibilities. If you buy (for example) from a bike dealer in Colombia, then only do the deal if the selling dealer can guarantee he can expedite the paperwork/title for you. Much easier for a local dealer to navigate the system than you. You go along and pay the fees as needed.

Lots of variations on this theme and the rules will always be changing and bribes will be payed. Es normal.

I think that so far as the various rules and regulations are concerned, driving the bike and crossing borders with a bike are two totally different matters.

So far as driving is concerned, the answer I gave above in post #4 should be sufficient.

So far as crossing borders is concerned, that really has nothing to do with the driver licence of the operator (assuming the driver is properly licenced), it has to do with whether or not the specifics of the vehicle registration and vehicle insurance are satisfactory to the border guards of the country being entered.

Michael