Sounds like a good 'un.
@Mice , as I've done a couple of 200s- planning to do one and a 300 this year (and most of my long-distance rides I tackle in the same vein), hope you won't mind me making a few suggestions.
Timing and pacing yourself correctly is key. Be nice and early at the start for signing on etc and to make sure you move off with everyone else. With that size entry, getting out into the sticks will be slow. It's definitely not a race, but there's a fine line between taking it easy and failing to make the cut-off. Remember that though you only have to do an average, door to door, of 9.3 mph, you will need to ride considerably quicker to give yourself time for food, controls, the odd breather, and anything else that might slow you down. By all means ride with a group if you find one riding at a comfortable pace, but you have to do your own thing- too fast or too slow and you'll do yourself no favours. 12 mph rolling would give you just over three hours spare for stops. It helps if you know the route- I ended up getting the wooden spoon on my second 200 on account of 'detours' that added a good twenty miles, the first one I ended up packing as I'd done 51 miles to the first control instead of 50-odd km...(the organiser in question doesn't do GPX files, not a problem you'll have). Can't remember if you've got a Garmin or other nav system, but paper backups are always a good idea. If the route sheet's not absolutely clear to you, ask someone about it beforehand.
Kit: Strip it down if you can (yes, yes, I know I can talk...). Make sure tyres, lights, batteries etc are in the right condition. If you're using sat nav, you'll want some form of external power pack to make sure it lasts the course, using them for directions is far more power-intensive than just route-logging. Try and avoid faffing at the controls.Time you don't spend off the bike means time in hand. I'd suggest a quick snack at the 50km control, bigger meal at the half way mark, another snack at 150km or so. At least, that's what works for me. If you need to eat more often, do, of course.
Oh: And enjoy it. Apart from the obligatory, secret clause in the AUK regulations that means at least once you'll wonder why you didn't just stay in bed