The best cure for all of this...
Rather than giving catchers access to public services, Nominet could build a user interface where catchers login and load the domains they want to poll and domains can only be loaded the day before they drop (This means they can't login on the day of the drop and adjust the domains they have in their poll list)
Nominet could set a default where every account polls for 200ms thus covering 24 hours, once that the domains that account has loaded have dropped then the account finishes for the day (The user will not be able to login and add additional domains to chase that day because this needs to be done 24 hours before the drop date)
What would the benefits be...
1) There will never be any flaws again in Nominets systems because people won't have public access
2) Every account polls at the same speed regardless
3) Nominet will see a clear pattern in members logging into accounts at what times and what domains get loaded
4) If you have two accounts you will not be able to strategise with chasing patterns and speeds throughout the day (If you did have two accounts and you loaded one domain on one account and one on the other... when one of those domains drops you will not be able to login and put the same domain on the other account because again this would have to be done 24 hours prior)
5) This would put a stop to 75% of the current problems