I got a response from support. I hope this helps anyone else facing the same issue as myself.
Current available smarty variables for messages sent from CRM addon are:
[fields] => Array
(
[] => Array
(
[id] =>
[type] =>
[active] =>
[name] =>
[description] =>
[data] =>
[options] => Array
(
)
)
)
[resource] => Array
(
[id] =>
[name] =>
[status_id] =>
[email] =>
[phone] =>
[priority] =>
[type_id] =>
[admin_id] =>
[client_id] =>
[ticket_id] =>
[created_at] =>
[updated_at] =>
[deleted_at] =>
[status] =>
[client] => Array
(
[id] =>
[firstname] =>
[lastname] =>
[email] =>
)
[ticket] =>
)
[company_name] =>
[company_domain] =>
[company_logo_url] =>
[whmcs_url] =>
[whmcs_link] =>
[whmcs_admin_url] =>
[whmcs_admin_link] =>
[signature] =>
[date] =>
[time] =>
Where resource is contact detail information
You can find fieldID in Settings → Fields
So example of it in action.
I have a custom field with the ID 9 and I want the customers details to be field in.
So I do the following:
{$fields[9].data}
if you want to see all values available to you put this in your email ether via direct send or via WHMCS email template:
{$fields|@print_r}
Hope that helps.