There are no real pitches for ladder work in Dowkabottom and the duck is very near to the entrance.
I suspect the water will be high in the area of the duck over the coming days.
You might be better going somewhere like Dow Cave (weather permitting). Assuming the Hobson's Choice choke is safely passable (check the boulders!) you might might use your ladder & lifeline on the waterfall beyond, which normally has to be climbed (but isn't especially easy for novices). Even if you limit your trip by turning round at that choke, it's still a very fine cave with much of interest. But do check weather forecasts as the stream quickly becomes scarily big and there's a risk of being trapped if it comes up. This nearly happened to a group I was with as a very young caver and the place rapidly became quite hostile.