apostrophe - Dickens' or Dickens's?

This BBC report (link) suggests that we should use "Dickens' Great Expectations", but I remember there is a rule from Strunk and White (here) that would suggest "Dickens's Great Expectations".

Is this just a difference due to British English vs American English?

BBC's report:

Armagh, Banbridge and Craigavon Borough Council's grammatical error
appeared on an advert for a performance of Charles Dickens' Great
Expectations in July.

Strunk and White

Form the possessive singular of nouns with 's.

Follow this rule whatever the final consonant. Thus write,

Charles's friend 
Burns's poems
the witch's malice   

This is the usage of the
United States Government Printing Office and of the Oxford University
Press. Exceptions are the possessives of ancient proper names in -es
and -is, the possessive Jesus', and such forms as for conscience'
sake, for righteousness' sake. ...