Awesome, Freddie ftw, shame that the only thing that works on our server is the sound when uber is activated, or is it just me?
That's correct. sv_pure is set to 1 on the server, which means all content files are taking from the GCFs save those in the server whitelist. In this case the server whitelist contains, well, everything I asked for it to.

Basically, when I was creating WDG skins I got our glorious leaders to edit the whitelists to allow for everything I created. This included a replacement for the uber sound. Umm, "Lovefool" by The Cardigans. It made me giggle! The other associated medigun sounds however are not allowed.
I could advise deadly on how to edit the whitelist further if he so wishes.