Asked my client to check all have been updated, she assures me they have so as she says we must be missing something.
Client reply below:-
Nope. We must all be missing something.
As far as I can see there are only two files that need changing:
1. MailFormatting_PHP.php, and
The first has just one instances of Split on row 42, the second has 6 instances on rows 152, 330, 389, 587, 590, and 660. I did a global search over the whole site, so I don’t think I can have missed anything.