Assuming you are in the right place and seeking to answer your questions, the Incinolet website says it uses 1.5kWh per cycle. That's probably a non-starter on most UK inland waterways craft, which in the main tend towards low voltage (12V), low current electrical installations. Many have inverters mainly for infrequent use, and some have engine-driven mains generators, but most would regard that level of power requirement as excessive.
(Sweeping generalisations are always a bad idea, and no doubt all the exceptions to the above will be along shortly with detailed descriptions of their electrical installations )
Folding beds, or part folding beds are not uncommon on UK inland craft, but the usual double bed size is around 4ft. There are styles of boat and interior layouts which permit wider beds, but these are less common.
Hope that helps.