Ok, I have done this.

Copied the 'as installed' classic folder to another one that I have called classic2 in the following folders:-

includes\templates
includes\languages\english
includes\modules\sideboxes
includes\languages\english\modules\payment
includes\languages\english\modules\shipping

I have updated the template name in template_info.php as advised here and switched to my custom2 template which should at this stage be identical if I am getting it right!!

Two questions arise:-

1. My sideboxes have disappeared - any idea what's up??
2. Am I getting this completely wrong??

Any advice or comments appreciated.

Regards.
FTF