Success! Most of the dummy site is formed and things are becoming more intuitive. It's clear that Squarespace has absolutely masses of potential but the learning curve is vicious, and much trial-and-error is needed, there really is no easy way of learning it besides on the job.
I'm guessing some parts of Sideburn online will stay fragmented until the dust settles and we're brave enough to make the full switch. Even then, if it works, the need to consolidate everything under the Squarespace banner may not even be necessary, but that's a call for Gary and Ben to make.
Squarespace's adaptive ability is amazing though, there's no two ways about it. From desktop to tablet to smart phone, it's useable in so many ways. In a lot of ways, it makes the old site look exactly that – old.