I think they still do, but Courtenay are one of the few peeps other than LMF where you can get this upgrade. If you know someone who is breaking a 2.6 GSi Veccy then they have these calliper brackets fitted as standard. I dont know if the Astra and the Vecrta brakets are the same, but I do know that they dont list this part seperately to the calliper for the Vectra.
Hope this helps.