Thanks Lyndel for your help so far,

unfortunately the Marantz software doesn't have the ability to change the duration of the code which is an unfortunate omission and would have probably been the easiest route to fix.

I tried the three codes you gave and they had no effect on it, so I tried quadrupling to 0000 0071 00C8 0000 .... and no joy. How do you go longer still as the next one is 12C?

I did randomly however hold the triple one down and this turned the tv on which was bizarre given your comment.

Just need to work out how to use it the power on macro, I tried repeating the longest one three times but no joy.

Any ideas?