wrote ...
Thought I'd complete what worked for me , in case others walk this path.

The main challenge initially was that all I had was the database from the an old version of the E107 forum.
Thanks to GL700wing for getting me off the mark, I've added to that sequence:-

Create a new SMF 2.0.17 database and forum.
Import a backup of the E107 data to the new MySQL database (same server)
Install E107 to see an example of config.php so created ( and invoked via the SMF convert.php 'path_from' )
Edit config.php file and configure the required variables (for E107 the details details on lines 7-9 in the e107_to_smf.sql file).
Turn off strict mode on the mySQL server
Run the convert.php script from the SMF 2.0.17 forum folder/directory. turn on the debug option (?debug=1)
Covert.php invokes e107_to_smf.sql to fetch the data.
My database was missing a number of tables/columns that e107_to_smf.sql was looking for , presumably features added in a later release of E107. Editing e107_to_smf.sql as each error as thrown was the quickest way to proceed.

Job Done