The client is not available for purchasing. I believe it's bundled with the main ACM 7 software. Unfortuantely, the developers don't provide any download or information and if you want to obtain additional details, then you have to contact them using the phone numbers on their website or the contact form on the link below.
Contact form: http://www.innovationdigital.co.uk/solutions/alterian-acm-7.aspx
Note: They will explain you better and provide details on how to acquire the client.