Bit new to mod rewrites, but realising it's power and very cool. I can get rewrites working when the actual file is in the root but not working when in subfolders.

What I'm trying to do:-
I want the URL mydomain.com/groundcare/hire/mowers/ to go to the page at mydomain.com/groundcare/hire/show.php?cat=mowers

I've tried the following but just get 404 page not found.
Options +FollowSymLinks
RewriteEngine on
RewriteRule ^groundcare/hire/(.*)/$ groundcare/hire/show.php?cat=$1 [L]

I've been trying and going round in circles and I'm sure it's something simple so if anyone could point me in the right direction it would be greatly appreciated.

Many thanks!