Thank you everyone for all the suggestions.
The Digital break out board is powered - the LEDs are on. I will double check this though as it was not something that we verified.
We have tried with both the round and flat DB27 cables. Admittedly our flat ribbon cable has been damaged and then repaired as much as possible. I've checked the pins and it appears to be working correctly, but it does not hurt to re-check the cable.
From memory our I2C cable is around 50cm long, but I've never measured it. Checking with
http://www.esacademy.com/en/library/...s/i2c-faq.html In typical applications, the <maximum> length is a few meters (9-12ft).
Currently noise is not an issue - the read values are all zero.
I'll follow up tomorrow evening after the meeting, until then please continue making other suggestions of things to check.
Again, thank you all for the help
Steve