MerlIAV

I fear I can′t help you there very much.

Have you turned debugging on in your wp_config.php? This may provide some useful information. Also if you have access to the server logs there may be some information in the webserver logs as well as in the syslog (at least on Debian systems PHP logs errors there by default).

Sure no problem. I uploaded my modified version of the file here: https://pastebin.com/CkWfgqnT

The function starts at line 37, the relevant modification is in line 40.

Cheers