Joomla: Synchronise Users to contacts error caused by incorrect table prefix

Synchonisation fails in Joomla because of an incorrent table prefix. The user table in Joomla is jos_users the sync script looks for mos_users. Error is:

Sorry. A non-recoverable error has occurred.

Database Error Code: Table 'redrorg_db2.mos_users' doesn't exist, 1146

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error

Array
(
[callback] => Array
(
[0] => CRM_Core_Error
[1] => handle
)

[code] => -18
[message] => DB Error: no such table
[mode] => 16
[debug_info] => SELECT id, email FROM mos_users where email != '' [nativecode=1146 ** Table 'redrorg_db2.mos_users' doesn't exist]
[type] => db_error
[user_info] => SELECT id, email FROM mos_users where email != '' [nativecode=1146 ** Table 'redrorg_db2.mos_users' doesn't exist]
[to_string] => [db_error: message="DB Error: no such table" code=-18 mode=callback callback=CRM_Core_Error::handle prefix="" info="SELECT id, email FROM mos_users where email != '' [nativecode=1146 ** Table 'redrorg_db2.mos_users' doesn't exist]"]
)