… something very very simple with php… if you can pass a var to a page, then why not!!!
so i have gone back to this route… of php and encode json. And just passed the a few variables via the url… sometimes i overthink these stupid things…
<link rel="manifest" href="manifest.php?manifestmainname=<?php echo $company_name; ?>&manifestshortname=<?php echo $company_name; ?>">
Anyway thanks @Apple for your help. but it seems i just had to approach it differently