Thank you Beq! The Firestorm guides have actually been the ones I've used for the most part, even with the Second Life Viewer and Alchemy. Firestorm seems to have the best documentation for things like this.
I should have said excluded, rather than whitelisted. But yes, that's the guide I followed too,
I've submitted a ticket with SL now too, and someone is going to check there's nothing wrong with my account at the official end, but if that fails I may well pop into Firestorm Support as it seems to be the most helpful Support team if the online guides are anything to go by! I suspect it to be a hardware issue, rather than an account issue, I just wish the softwares were verbose enough to tell me *why* these things are failing.