Finally got the council tax bill, so I can go ahead and book my Life in the UK test. The online booking asks for my Home Office reference number, so I dug out my 'grant of leave to remain' letter from my most recent FLR(M), and that doesn't have a reference number, but a 'Case ID'.
I know I'm probably being overly prescriptive in making sure the terminology matches up, but are Home Office reference and Case ID in effect the same thing?