Thanks for the replies. This beer was really fun to make. My friend was putting a recipe together, and we decided on the maris otter malt, but I didn't know how much he wanted to use, so I got 15 lbs to be on the safe side. We then decided that it'd be pretty cool to use a huge grain bill. And this is the largest amount of grain I've ever used in a 5 gallon batch, so it was good times. Our efficiency is a little low, unfortunately, but I blame that on the large amount of water in the mash tun, and the relatively little amount of sparge water. We could've sparged longer and compensated with a longer boil, but I guess I'm okay with 5% lower efficiency.
We're pretty excited about this, but I imagine it's going to take quite some time to ferment, and then lots more time to age. It's hard to be a brewer when you're a rather impatient person!