Hey Ray,
Cheers for your response. Yes, you are correct, the sensors are definitely 3.3V. I didn't think of this, so thanks for pointing it out. I made a noise generator last week with a L7805cv voltage regulator so I guess it would that would do the trick? You reckon I'd only need one resistor once that's taken care of then?
My apologies, I meant to type 4, not 5! However, I would prefer the installation to be larger, and I wasn't aware of soft-i2c buses. As I'm trying to avoid using something like the PCF8575 I2C Expander, that's really helpful information.
Thanks a lot Ray!
Jonny.