I think I might have some kind of virus or malware on my Macbook.....

[orangina]

..... any idea what I should do to check? I don't just want to throw myself at the mercy of google, any recommendations would be very gratefully received.....

Thank you!

Macs are well-nigh universal in the security research work

They certainly weren't at McAfee when I worked there. The only Macs around were for those working on security software for Macs. Everyone else used PCs.

No-one runs any form of "security" software

In that case they are idiots. Going back to McAfee again, the only computers in the business that were permitted to run without security software were those on the "dirty" network - a network within the virus lab used to store the virus collection and test new releases of software to ensure they detected and cleaned correctly. Every other machine in the business had security software installed and enabled.

I've yet to see a description of a security vulnerability in OSX which would have been blocked by add-on security software and would not have required you to repeatedly click "yes"

The virus researchers at McAfee could show you a few.

The first thing the apple teccy team told me to do at one of my " lessons" was take it off as it would slow things up

Apple like to maintain the myth that the Mac is fully secure. I know a lot of people in the computer security industry and I don't know any who agree with Apple on this. The only real security advantage the Mac has over a PC is that there is less Mac malware in circulation, but that is because malware authors know that there are a lot more PCs out there for their creations to infect.