There was no wash basin.
A bizarre underfloor heating system had been hand crafted from large bore copper pipe, and the main radiator circuit diverted to include it, thus destroying any natural flow assisted by gravity.
However because we were not ready for a full bathroom refit, we had temporarily reused the massive bath, but moved forward by 3 feet. We couldn't really bath in it, but it could still be used as a large shower tray. We have survived this way for several trips, and general living aboard at the mooring.
However we have now decided that refitting the new bathroom should be our next priority. My previous post explains that we have already had to move the calorifier, (the hot water tank), to one corner of the bathroom. Some space has been used up, as a result, but it was really the only way we could put back a system that worked, (and could be worked upon).
We are happy we have a way forward. Unfortunately actually getting our preferred parts has proved harder, and we have not been able to order up our first choice of bath in a time frame that is acceptable. So in fact the sketch-up images already need modifying, as the alternate choice of bath will not now be one with a seat in it.