Scrollphat not working anymore/

Hi.

I had scrollphat working nicely on a pi zero. I used the sd card for something else and have now put another one in and installed VERSION="8 (jessie)".

i have done apt-get update and upgrade and enabled SPI and i2C but....

.... whenever i try to run one of the example scripts i get this error...

Traceback (most recent call last):
  File "ip.py", line 12, in <module>
    import scrollphat
  File "/usr/local/lib/python2.7/dist-packages/scrollphat/__init__.py", line 8, in <module>
    controller = IS31FL3730(smbus, font)
  File "/usr/local/lib/python2.7/dist-packages/scrollphat/IS31FL3730.py", line 21, in __init__
    self.set_mode(self.i2cConstants.MODE_5X11)
  File "/usr/local/lib/python2.7/dist-packages/scrollphat/IS31FL3730.py", line 62, in set_mode
    self.bus.write_i2c_block_data(self.i2cConstants.I2C_ADDR,    self.i2cConstants.CMD_SET_MODE, [self.i2cConstants.MODE_5X11])
 IOError: [Errno 5] Input/output error

Any help or ideas please?
It had been working like a dream but now.. it's not :(

Cheers, Don