Michael avoided dealing with Seymour, but would occasionally contact him whenever he needed detailed information on or access to special weapons. Seymour was occasionally frustrating to deal with due to his overenthusiastic personality, especially with regards to the spy trade, but his knowledge and contacts were quite valuable on occasion.
As shown in the file below, as part of Olivia Riley's campaign to cut Michael off from those who had helped him in the past, Seymour was captured and deported from the United States.
Family name is Talbot as seen in his file.
"Don't argue with destiny. It will kick your ass."--Seymour talking to Fiona Glenanne