Hey there Confusedmum,
I apologize about the late response on this thread, thank you for being patient! Were you able to figure that TV brand issue? If not, I'd be happy to help out, since I understand it's not clear where to go from there. What I recommend is that you look up TV remote codes online and see which brand shares the same code as Pendo, then try that brand's setting and see if it works. I would also recommend that you submit feedback via Google TV to let Google know that you would like to see support for Pendo added in the future.
I look forward to your response, and if you have any other questions or concerns for me, please let me know!