Thanks very much for your reply Peter.

I contacted the Loewe importer in New Zealand yesterday and spoke to one of the technicians.
I asked about the frequency that they transmit at, but he said he didn't know.
He did however say that they used the same codes as Panasonic.

I tried each of the Panasonic codes in the OzTivo slice, but none of them worked :-(

In other news, I heard back from the Loewe Helpline in Germany (via the Loewe helpline in the UK). Their response was:

"frequency is 36 khz, TV uses RC5 code, VCR Kaseiko code"

I'm too sure where I should go from here, or whether I should just give up and get a PAL tuner installed sooner rather than later...