Hello Graham,
Tutman's is definitely a low water trip. We did it in reasonably dry weather (i.e. it hadn't rained for a couple of days) and I'd say that it would definitely be impossible if the water was any higher (average or above average conditions). As you've seen it takes a pretty big (and very cold) stream, and getting trapped on the far side of the duck would most likely prove terminal!
My advice would be to wait for a nice dry settled spell, and to take a wetsuit! It's definitely worth the effort though.
The best people to ask about the shaft is probably the Moldywarps, as they are the local 'experts':
http://www.caving.uk.com/Resources/Pages/clubs/moldywarps.html
The DUSA dig is dormant at the moment, although it does have great prospects for breaking into new passage (in fact 8' of passage was 'discovered' on the last visit). It's on the north side of Swaledale, and we've named it Langthwaite Pot. I'll let you know when we break through in to caverns measurless :wink: The problem is picking up the motivation to scrot around in some horrible hole, rather than do some ace trip, or go climbing.
Any luck down Oddmire yet?
George.