Sorry of my late replying. Last week, I called Assistant Professor Sawittree Chareunbongs, Division of History,Faculty of Arts : Chulalongkorn University.
Based on her MA. Thesis(Western Community in Bangkok) , there’s no prominent historical evidence concerned to the Russian Community in early the 20 century. However, at the end of Sathorn Road, there is the beautiful old building that used to be rented from the Crown Property Bureau as the USSR’s Embassy during 1948-1999.
The building was constructed by Luang Jitrchamnong Wanich(Tomya Rongkawanich) in 1888, during the reign of King Rama V. After the business of Luang Jitchamnong Wanich had been lost, the house was took over by the Crown Property Bureau.
In the reign of King Rama VI, another source said that the King gave the house to Phraya Ramrakop (ML. Phoeu Peungboon Na Ayutthaya) but later, he sold it back to the Crown Property Bureau again.
After that, reliable documentation (rental paper) between the Crown Property Bureau and the USSR Government indicated that the USSR signed the paper to rent the former Thailand Hotel to be its embassy in 1948 until the year 1999.
According to security reason, I agree with Aj. Theeranan that relation between Thailand and the USSR during the Cold War filled with suspicious. My teacher used to go to the USSR Embassy once to applying for higher education scholarship and he was tracking by spies of the government all the way to his elder brother’s office (National Intelligence Agency).
Architectural style of the building had been taken from the model of the Italian villa of the 19th century(http://www.crownproperty.or.th/cpad/vtr_8.php)
In generally, being such a community must to have a church, a school, a village or at least a club, however, last week, my friend Aj. Sranmitr Pracharnsith, Naresaun University , suggested a document revealing that long time ago, a Russian had made a quarrel with his friend in a club may be in Silom or Bangrak. But no document referred to any Russian descendant.
If the Russian Community in the letter of Miss Victoria Kudriavtseva means the former USSR’s Embassy, it locates at 1/108 North Sathorn Road , Silom Sub District, Bangrak Bangkok, and being develop to be the spa place and boutique hotel of the One Sathorn Project at the present day .