Not really a lot of help as we're not afloat at the moment, but just wanted to say that I've read all of this thread and am humbled and awestruck at the level of concern, co-operation, support and down-right "putting ourselves out" type effort going into this. Well Done everyone: this is a fantastic effort by all concerned and I truly hope this boat gets found.
Just to add though ... whilst we're not boat owners at present, we do walk the network a great deal, especially the Ashby. We were there on Sunday afternoon (parked in Snarestone outside The Globe and walked south from the tunnel) and saw a guy busily building a very crude ply wood and timber frame/screen around the back and front of a boat, so as to almost conceal what was going on at either end. Boat was moored a few hundred yards down, facing towards the tunnel.
The rear construction actually had a large slot in it for the tiller to go through - it was almost chest high to the guy who was building it and would certainly conceal the distinctive rear of the missing boat. I'm now kicking myself I didn't get any pics of the thing. At the time, it was painted grey but could be any colour by now. I have no idea if this is relevant. If this was you and your activities were both legitimate and logical, then I apologise for any offence, but it just goes to show that it's possible to change the look of a boat quite easily with a bit of paint and some timber.
Keep up the great work everyone.