.htaccess and '410 Gone' help please

I've around a 1000 non-existent urls indexed that I want to return a 410 and not a 404.
The urls all have the following in common

http://mydomain.com/[1 or 2 numbers]-[numbers and letters]
None of the urls have a file extension.
e.g

http://mydomain.com/4-11055981-B001394530-Nioxin_Intensive_Therapy_Recharging_Complex_90_Count_Bottle
http://mydomain.com/35-301188-B001UO651S-5_Pack_Premium_Reusable_LCD_Screen_Protector_with_Lint_Cleaning_Cloth_for_Apple_iPhone_3G_8GB_16GB_Accessory_Export_Packaging
http://mydomain.com/33-Watches

Code (markup):

I'm trying to match any url that starts with 1 or 2 numbers, followed by a dash and followed by any combination/length of alphanumeric characters after the dash.

I've added the following to my htaccess, but I'm still getting a 404 instead of a 410

RewriteEngine On
RewriteBase /
# Check for HTTP/1.1 request Host header
RewriteCond %{HTTP_HOST} .
# Make sure the requested file does not exist
RewriteCond %{REQUEST_FILENAME} !-f
# Return 410-Gone for HTTP/1.1 requests for non-existent files
RewriteRule ^[0-9]{2}-(.*)$ - [G]

Code (markup):

Any help appreciated

 

Just curious... What happens if you end your RewriteRule with [G=410]?

 

Ok, have it working, it seems WP doesn't handle 410's
So I had to explicitly add the path in htaccess

ErrorDocument 404 /index.php?error=404
ErrorDocument 410 /wp-content/themes/mytheme/410.php

Code (markup):

and add to my custom 410.php the following as

<?php get_header() ?>

Code (markup):

didn't work

<?php define('WP_USE_THEMES', false);
require($_SERVER['DOCUMENT_ROOT'].'/wp-blog-header.php');
get_header();
?>

Code (markup):

@rainborick Adding [G=410] doesn't seem to change anything. Header status code is 410 either way.

Only issue is that my rewrite rule only works if there are 2 digits preceding the dash. If only one digit, it reverts to a 404. Off to do some more regular expression reading

 

All working perfectly now...

# Check for HTTP/1.1 request Host header
RewriteCond %{HTTP_HOST} .
# Make sure the requested file does not exist
RewriteCond %{REQUEST_FILENAME} !-f
# Return 410-Gone for HTTP/1.1 requests for non-existent files
RewriteRule ^[0-9]{1,2}-(.+)$ - [G]

Code (markup):