Nasty bit of code - I was having weird crashing problems with Delphi on my machine and as part of my attempts to fix it ended up disabling my anti virus for less than 5 minutes - within half an hour of that it had presumably sniffed my FTP details from Dreamweaver and uploaded itself to our site, as well as completely shafting the computer.

Cleaned computer with Malwarebytes, changed FTP password and re-uploaded website and it seems to have gone. Ended up having to wipe the whole machine in the end as problems were getting weirder and weirder - not sure if it was the virus that broke Delphi, or the Delphi problem was separate and the virus sneaked on whilst I was trying to fix that.

Still, all's well that ends well... least it wasn't on the website for very long.