Is it permissible to pray two by two or three by three during work for 12 hours in a textile factory, and is that considered abandoning congregational prayer and prayer in the mosque, and is it permissible to work in a factory owned by a British Jew?

There is no harm in congregational prayer at the workplace if a congregation is available, for attendance at the mosque is not obligatory for one who finds a congregation. It is permissible to work in a factory even if its owner is a non-Muslim, as long as the work itself is Islamically permissible.