Re Spannatime's question;
"Is there any official news from NPAS which units are planned to be 20 hours and which will be 24/7?"
Does NPAS have access to the daily logs from all the different units for the last couple of years?
If so I think they will be looking at who is busy in the early hours/mornings and who isn't.
Air support seems to come into its own at night I have found, but is relatively quiet after 2-3am, till about 4pm the next day. Not counting any photo requests during the day.
Strathclyde seem to make it work and they finish early. Maybe a visit to their unit by NPAS might be an idea to see how its done?
The cross border ops should help when the various units lose their a/c for a week or so for maintenance checks.
Things might change re hours flown come April. I know the large North Yorkshire force who havent havent got any air support except the volunteer flyers, are waiting to request I55 from Cleveland come D-Day, without worrying about who is going to pay at the time