Spoke to my hosts and we switched the PHP from a rather old 5.3 to 5.6 or 5.7 and that seems to have sorted it
Thanks for your responses, everyone. I just tried to upgrade my PHP version, but turns out that the highest available on GoDaddy is 5.4, which I am already running :-/ Sadly I’m not qualified enough to look into this matter in detail :-/ :-/