Hi NN
If you do decide on a boat – prices in February can be very reasonable. You could try ringing Woods, Freedom and DRL. Ask about prices, you might be pleasantly surprised. DRL for example are offering 2012 holidays at 2011 prices if you book before the end of Dec and I’m sure other yards will have similar offers. Worth speaking to them direct.
I’ve been out in winter many times (including the snow last December) and with the warm air heating you are snug as a bug, honestly. You can’t beat it.
Strowager is right to point out about the conditions, places like Ranworth and the Ant above Barton can and do freeze in severe weather. However the main rivers should be OK. Water can be a problem but there are places where it can be obtained all year – DRL, Freedom and Woods as mentioned, Ranworth as long as its not frozen, Ludham Bridge, Boulters, Horizon often have a hose connected in winter, Moonfleet, there are others. The Southern rivers are more of a problem. It just needs careful planning. And yes, the great beauty is you can, and do, cruise all day without seeing another moving boat.