Martin_123
You are quite correct, BGS are not on the list of sponsors. The only one I could find was CTC, but I didn't look very hard, so I may have missed some.
As I said in my earlier post, most of the schools decided that getting the approval simply was not worth the effort. At the time the vast majority of foreign students were from the EU, so they did not need the visas. The much smaller number of non EU foreign students did not generate enough business to make registration worthwhile. But after the UK leaves the EU, the much larger numbers will probably make the schools reconsider their decisions.