Hajur is perfectly fine. In Nepali Byakaran (Grammar), the words used in addressing someone are classified in this way:

तँ, तिमी - निम्न आदारार्थी  (Ta, Timi - Less Respectable)
तपाई - आदारार्थी  (Tapai - Respectable)
हजुर - उच्च आदारार्थी (Hajur - highly Respectable)

Hajur is frequently used in Bhanubhakta's Ramayana and other old generation books. Baksyos is also used, but less frequently to address Monarchs and Royalties. However, Baksyos etc are derived and modified Persian words, that were imported by the Shah clan who had Iranian roots. There is a lot of similarity in the interior designing of the Persian, Moghuls and Shah palaces, arts, life style and some similarity in language. Shahs are Persian Muslims by roots after all. They came to Nepal with lots of money and might, took power and accustomed themselves with the local Hindu tradition. And even made the locals believe that they were the reincarnation of Bishnu Bhagwan. hahahaha

The courtiers had to address the royalties with Baksyos. They copied the words and used them at their home. Once upon a time a Monarch heard his courtier's family member address the courtier with a Baksyos. The king was not pleased. So since then, the courtier would address the king as gariBaksyos, sawari bhai Baksyos etc and the courtiers would address each other as garisiyo, gaisiyo etc. The courtier's neighbors  overheard it, found it posh and funny and some of them used it. Thus the words spread. I have seen some normal people use tapai/hajur before, and after accumulating some wealth and having a nice building, upgrade themselves to gaisiyo etc. This is called typical copying tactics of desperate Nepalis TCTDN. Although I smell sycophancy  in gaisiyo/khaisiyo words, I don't really hate those who use them. After all they are fellow  citizens.

Now lets send Gyanendra and co. back to Tehran to meet up with their jiju khanatis.

thx
Rohit

PS the above story has some twist and turns  but more or less true IMHO.