Yes, this is the traditional recipe. I prefer to make my own custard or creme anglaise with real vanilla, as Bird's is a bit too sweet for me. You can use any suitable fruit too: tinned mandarin oranges is nice (try swapping the sherry for a mix of the juice and some orange liqueur).
The only thing I do differently is use cream sherry. This is THE sublime English trifle! Rich beyond belief and absolute perfection!