1tulip asked me a while ago about training a retriever on rabbits.
In a UK Field Trial ground game is nearly always present so you have to be prepared for it to be flushed (dog stays steady does not put in a chase) and subsequently shot (sit to shot, mark if possible, then retrieve). I thought it might interest you guys to watch this wee movie; not a professional production but the quality is good enough to see what's going on. Some nice work to be seen with "cross line" retrieves; and a very good wee cocker doing the flushing.
This is pretty typical rabbity hill country; broken ground, stone walls, tussocky grass, plus a few whins and drainage ditches. I'd guess it's in North Yorkshire, but there's a zillion acres just like it in Scotland.