For many years, however, there have been very large numbers of international students doing cheap post-grad courses
Just from the unis that would normally be found in the various league tables these are the 20 with the highest international percentage of postgrads (all so both taught and research. As you indicate @LondonLawyer the mix is not the higher, or in many instances even mid ranked unis. LSE and Southampton are at the upper end do both feature, and there are two more specialised arts unis. But even discounting those four, still leaves c.85,000+ PG students
University for the Creative Arts 87.8% 1,910
University of Bedfordshire 83.3% 4,510
Ravensbourne University London 82.5% 400
LSE 78.1% 5,740
The University of East London 76.0% 8,410
The University of the West of Scotland 74.0% 4,890
The University of Greenwich 73.7% 8,285
University of the Arts, London 72.7% 4,440
University of Hertfordshire 71.7% 13,440
Coventry University 71.1% 9,325
Glasgow Caledonian University 71.0% 5,250
The University of Southampton 70.5% 7,270
Teesside University 69.5% 7,475
De Montfort University 69.2% 4,670
The University of Bradford 69.1% 3,285
Roehampton University 68.8% 4,155
Brunel University London 68.4% 5,190
York St John University 67.8% 2,245
Solent University 66.2% 715
The University of Westminster 66.1% 3,180