Thanks very much, Marvin!
The past subjunctive is still common in BrE where the condition is open, e.g.
1. If I were you, I'd buy a different hat.
2. If that were the case, we would all need to do X.
The past indicative is always used however where the fact in the if-clause is accepted as true, e.g.
3. If that was a little green man in that Mercedes, we'd better follow him and get a photograph.
(What would you say for #3, out of interest?)
MrP