Welcome to the forum, we travelled all over the country looking at different caravan layouts, and finding out that there were certain things we didn't like about some caravans. ie, circular sinks, caravans with showers in the toilet. Etc.
When you say a fixed double bed, there are fixed side beds, island beds, across the way, and island beds normally at the back of a of the van.
Some dealers will give a "Starters Kit" aqua roll waste water carrier, new battery and in our case a full sized awning, we thought great but we used it twice, too heavy, and awkward to erect , others of course will erect a full awning for a Friday to Sunday away.
Good luck in your search.