Managed to find an outfit which is the NZ distributor for an emulator - about 250GBP installed - which should cure the tachograph issue. Thanks for the heads up guys, I would not have known to go down this track if I didn’t get the link above.
Of course, the chap linked above wanted 500 pounds(told me to ignore the website pricing) so that was a bit of a laugh. But it did set me down the right path!