You can use the SQL code below: 

TRUNCATE TABLE `***wp_***wpforo_reactions`

Use PhpMyAdmin plugin or the same tool in your hosting cPanel, go to the SQL tab and execute the SQL.

Make sure you have a backup of your database.

Also, please make sure your table prefix is wp_, if it isn't, change the red marked wp_ prefix to yours.

I would like to fully remove all trace of the like dislike option from my forum, unless I'm missing something, I cannot see an easy way to do this.

I have removed the ability for all my members to be able to see the like/dislike buttons, by removing specific user permission control from each of the forum "Accesses".

Although I have now purged the reactions cache, which has helped me greatly with regard to free inodes, all the likes and dislikes obviously still remain in the Database. I would like to know if is there a simple way/routine that can be actioned to purge the database of all the likes/dislikes?

If someone could advise or help with this, it would be greatly appreciated, as I do not have the knowledge to be able to do it.