Buzzing noise in dash area

[Saturbo]

I recently had this annoying buzzing noise from behind the dash start and its getting worse now. Sometimes you can switch off the engine etc and start again and it doesn't happen.
It will do the buzzing noise with only the ignition on (ie no engine) so i'm pretty sure it not engine related.
I can also hear a gurgling noise as well just before the buzzing starts - is there a pump or something behind the drivers dash area to do with the heating etc?