There has been similar questions from several members on how to become Platinum member so please refer to the followings;

Please visit the top 'Home' page of this site and in the middle, you will see 'Contributions to Support the Website [ become Platinum member ].

In case you have difficulties finding it, please refer to the following link;
http://www.nsxcb.co.uk/content.php?23-Contributions-to-Support-the-Website


Thank you.

Regards,
Kaz