But honestly: I think you are right, but do you have a proof for it, like an online photo with her name? The fact that she is ( http://server3.nudecollect.com/picture/25338/category/644-2003_11_21_on_location_gina_b_jo_peaches_a_vera_a_c9984 ) in the "On Location" photoset to the film "Forbidden Fruits", where Silvia is not part of, seems to indicate that she is not her mother indeed.
If she is Viv Thomas's wife, then she should be Avril Mouton http://www.imdb.com/name/nm1394430/?ref_=nmbio_trv_3 , and their common daughter is Chantel Thomas http://www.imdb.com/name/nm1392776/ . Apparently Avril works as a makeup artist and hair stylist for her husband. (There was an Avril Mouton who participated at the Miss South Africa election on 1979-08-25. But Mrs. Thomas became 14 just that day, so these two are most likely two different persons.)
By the way, there are lots of sets on http://www.nudecollect.com/ . Among them (at least) the following Viv Thomas sets with Silvia: http://server3.nudecollect.com/index/category/417-2002_12_27_foot_lovers_close_ups_silvia_saint_f45db http://server3.nudecollect.com/index/category/540-2003_06_06_on_location_eve_angel_gina_b_jamie_a_janine_b_jo_silvia_saint_tara_a_76330 http://server3.nudecollect.com/index/category/668-2003_12_31_silvia_saint_silvia_saint_1c6bb http://server3.nudecollect.com/index/category/718-2004_03_12_silvia_saint_silvia_saint_f0edd http://server3.nudecollect.com/index/category/920-2005_01_21_bums_panties_sandra_shine_silvia_saint_9dd18 http://server3.nudecollect.com/index/category/1049-2005_08_26_bums_panties_jo_pocahontas_a_silvia_saint_8fa79 http://server3.nudecollect.com/index/category/1050-2005_08_26_silvia_saint_silvia_saint_ccc6c http://server3.nudecollect.com/index/category/1083-2005_10_28_foot_lovers_close_ups_silvia_saint_dd859 http://server3.nudecollect.com/index/category/1089-2005_11_04_on_location_evelyn_a_kylie_a_penny_flame_silvia_saint_35ff4 http://server3.nudecollect.com/index/category/1093-2005_11_11_bums_panties_silvia_saint_fd1ff http://server3.nudecollect.com/index/category/1108-2005_12_02_on_location_liz_harvey_natalie_birch_pippa_a_silvia_saint_70c10 http://server3.nudecollect.com/index/category/1115-2005_12_23_on_location_evelyn_a_penny_flame_silvia_saint_8bd61 http://server3.nudecollect.com/index/category/1128-2006_01_27_foot_lovers_close_ups_silvia_saint_3aae8 http://server3.nudecollect.com/index/category/1198-2006_05_12_bums_panties_silvia_saint_zuzana_drabinova_92c28 http://server3.nudecollect.com/index/category/1301-2006_10_25_silvia_saint_silvia_saint_804e8 http://server3.nudecollect.com/index/category/1417-2007_04_06_silvia_in_pink_silvia_saint_94feb http://server3.nudecollect.com/index/category/1517-2007_08_18_miss_europorn_silvia_saint_2c8f7 http://server3.nudecollect.com/index/category/1533-2007_09_05_uss_legs_silvia_saint_1828f http://server3.nudecollect.com/index/category/1534-2007_09_07_silvia_saint_silvia_saint_93ec6 http://server3.nudecollect.com/index/category/1554-2007_09_27_silvia_saint_silvia_saint_6a75b http://server3.nudecollect.com/index/category/1581-2007_10_24_toe_cleavage_sandra_shine_silvia_saint_d338d http://server3.nudecollect.com/index/category/1590-2007_11_02_tales_of_the_clit_silvia_saint_suzie_diamond_26603 http://server3.nudecollect.com/index/category/1642-2007_12_30_dressmaker_silvia_saint_90f56 http://server3.nudecollect.com/index/category/1736-2008_04_07_fit_silvia_saint_1568f http://server3.nudecollect.com/index/category/1938-2009_01_09_silvia_the_singer_silvia_saint_51b7f http://server3.nudecollect.com/index/category/1992-2009_05_15_silvia_saint_silvia_saint_8f5f1 http://server3.nudecollect.com/index/category/2115-2010_02_03_silvia_saint_silvia_saint_b1bea http://server3.nudecollect.com/index/category/2238-2010_11_18_silvia_saint_silvia_saint_41ee8 http://server3.nudecollect.com/index/category/2640-2013_06_08_saints_and_sinners_evelyn_a_silvia_saint_f4aa0
