I currently have an entire website running on PHP & GET variables.
My links look like this at present
http://www.example.co.uk/brochure.php?cat_path
Assuming your parameters are always named cat_path
and product_id
(if it exists) you can do something like this:
RewriteRule ^([^/]+)/([\d+])$ $1.php?cat_path=$2
RewriteRule ^([^/]+)/([\d+])/([\d+])$ $1.php?cat_path=$2&product_id=$3
Your URLs would then be in one of these formats:
pagename/cat_path
pagename/cat_path/product_id
For example:
http://www.bentinckfencing.co.uk/brochure/24
http://www.bentinckfencing.co.uk/product/35/54
Edit: I see you want to use product names in the URL. In that case, your PHP scripts will need to be able to take a name as a parameter and look up the ID. You should continue to accept the ID directly so as to not break existing links. Then your rewrite rule would look like this:
RewriteRule ^([^.]+)$ brochure.php?name=$1
And http://www.bentinckfencing.co.uk/Concrete_Fence_Posts would rewrite to http://www.bentinckfencing.co.uk/brochure.php?name=Concrete_Fence_Posts.