Don't know whether it's been said so far but this '20 minute dog' would also havto be a good size for a fox, not some big dull thing that would take 20 minutes just to reach the fox, it would havto be a case of straight on and harassing it before giving room to bolt. IMO not all 'failed' digging dogs can be 'good bolters', they still havto have something about them and to work the fox in a certain way.