Print to printer
Which does print what I want it to but displays the print dialog box.
I'd like it to go straight to either the client default printer or to a printer attached to the webserver.
After some playing around with PHP and Shell I've used the following method that works quite well. I thought I'd post it on here for others if they ever needed it.
Which basically prints $file to $printer (that is a printer installed on the server.)
shell_exec('lpr -P $Printer $file');