[Graham]

Yes, that's what we do also.

What about default time for a DNF?  We usually use the slowest time achieved on the stage regardless of class or era but have use 120 seconds in the past.

Also what about stage run time length? 60 seconds + end lap?

 I kind of guess that the clubs who have the stages will know best what works for them, and probably depends on the length of run of each stage which may differ.
So I don't want to be too prescriptive on those issues. But I guess we should have a Standardised DNF time at least, I will ask the guys at Wye Valley next week what they tend to use then we can decide between the hosts.