Thanks for this. Changing the array structure sorted it. This is what I used in case it helps others.
$arr = array(
‘properties’ => array(
‘company’ => ‘Biglytics’,
‘email’ => ‘bcooper@biglytics.net’,
‘firstname’ => ‘Bryan’,
‘lastname’ => ‘Cooper’,
‘phone’ => ‘(877) 929-0687’,
‘website’ => ‘biglytics.net’
)
);
$post_json = json_encode($arr);