We must recall that Mr. Steele was not in the employ of Her Majesty's Secret Service, or of the government in general. As such, one cannot properly claim that "Great Britain" interfered with our election.
Here is an interesting article:
Trump Russia dossier key claim 'verified' - BBC News
Now, if the Republicans desire to order an investigation into Mr. Steele, they have the right to do so. Oddly, however, no one has called for such an investigation.
If I were the OP, I would call his or her Senator, and demand such an investigation, being sure to explain how Mr. Steele and those that hired him interfered with the US election.