Who is Captain Trevor Nash-Burnham from The Piano Tuner and what is their importance?

Captain Trevor Nash-Burnham is the officer who meets Edgar in Mandalay and shows him around the city. Nash-Burnham is friends with Khin Myo and seems to feel a similar respect and curiosity for the local culture that Edgar feels. He has clearly dedicated time to learning about the Burmese people and their legends, as he recites the myths behind the street plays they are watching. He enjoys Edgar's company and seems to be pleased that he has a more sympathetic person to spend time with. He is sick of the other British officers who do not care anything about the Burmese or their culture. He comes across as a very likeable character.