there's no such thing as the accepted English spelling of Hindi. there are 4 or 5 popular transliterations, and recently I see that divesting vowels of their final -h is getting popular; 'wallah' and 'pukkah' are slightly archaic.
Isn't "wallah" the accepted English spelling? And some of the wallahs are hyphenated while others are not. Unless this is deliberate, shouldn't there be a standard way of spelling this type of compound word?