301 redirects using htaccess and reg exp

Hi
i am trying to use my htaccess file with regular expressions perform 301 redirects on links that Google would class as duplicate content. Effectively paroduct pages that are accessed via category and sub category links.

Example of one product, there are 614 products in all in 4ish categroies each:
All of these pages:
http://www.thesweetiejar.co.uk/retro-sw ... ets-100004
http://www.thesweetiejar.co.uk/retro-sw ... ets-100004
http://www.thesweetiejar.co.uk/retro-sw ... ets-100004
http://www.thesweetiejar.co.uk/sweet-fl ... ets-100004
http://www.thesweetiejar.co.uk/gelatine ... ets-100004

Need 301ing to the canonical URL:
http://www.thesweetiejar.co.uk/barley-s ... ets-100004

SEO Freinedly URLs are switched on and OC version is 1.5.4

Thanks

Isn't that the point of a canonical tag, to offer one url for the product regardless of the category stuff in between the domain and the product name in the url?

Simon

This exercise is to cover old links that may be book marked or indexed after I have done some seo restructuring on my clients website.

These links don't actually exist as links within the site anymore but as the site is 10 years old they will be linked to externally and they are being picked up as duplicate content still on google webmaster.
To make sure I cover all these links (as there will be around 2500) I want to do it with reg exp rather than manually having a list that big in my htaccess.