[pen] ASAP, basically. We've moved in 1998, 2000, 2003 (twice), 2004, 2006, 2011, 2012, 2013. It doesn't get easier, as we have more stuff every time we move, but we are better at it. Twice we've done it at a week's notice, which adds to the fun!
I suspect your move might be harder than most due to it being the Windy Miller's first, so good luck!

[Phil, Duj] I think you're both right. I moved in 1997, 1998 (twice), 1999, 2007 and 2009. I may have forgotten how much I hate it, but I'm so looking forward to the new house. It'll be good in the end. It's perhaps 15 or 16 rungs up the property ladder from our tired old terraced house. Now... how to transplant the sapling hazelnut tree grown from a nut found under a hedge during a picnic while on holiday in Brittany which is hanging onto its leaves. I'm going to start digging a ring around the roots - a bit deeper every few days - so that we can lift it in a couple of weeks.

Does the new place have more storage space / shed space? if so, you can't go wrong :)

[penelope] good luck with that. Expect the wretched thing to go into shock for two years anyway.

Hard to say about the storage thing. It has fewer cupboards, but more rooms, and it has hidey-holes in the 'berging', the Toblerone-shaped spaces over the eaves created by bedrooms up in the roof. But I'm aware that if I shove box after box into the berging spaces, they might be shuffled so far away from the access hatches that I'll never see them again, and neither will anyone else until the house is eventually demolished. (Oh no. I've just put into words the fear that will become my house-moving nightmare for the next 6 months.) There's also a garage under the house and a big (and properly roofed) space under the massive deck. This morning I gave ALL my money to the solicitor; I don't have a running-away fund any more. Eeek.