Question

The model millionaire a wedding present to hughie erskine and laura merton from an old beggar why do you think the baron did not write from baron hausberg

Answer 1

Hughie’s accidental meeting with Baron Hausberg turned out to be quite beneficial for him. Baron was dressed as beggar to get a portrait for himself made from Trevor. Hughie did not know the reality about the Baron’s affluence. Hughie, thought he was a real beggar and gave him a sovereign; Hughie’s kindness impressed the Baron.

Since Hughie had helped the Baron considering him a beggar, the Baron had liked it.  He did not want to make Hughie feel uncomfortable. So, he just wrote from an 'old beggar', instead of his real title.