Planning for MINI-WC - toilet + washbasin side by side?

Hello hello!

I am new here in the forum but have read several times before.

We want to renovate my grandmother’s (very) old house. Her living rooms are on the first floor and her bathroom is on the ground floor. She has difficulty climbing the stairs several times a day. Therefore, we would like to build a small toilet on the first floor.

For this, we would use a part of her storage room (with window).

The storage room is about 1.40 meters wide. The small WC should have a length of 1.00 meter so that grandma still has a small storage surface in the room. We would have the door (76 cm) swing "outwards" to save space in the bathroom. We would like to use the pre-wall installation version for the toilet.

There are 2 windows in the future WC. Therefore, 2 walls for the washbasin are not available. Only the wall where the toilet will be placed (1 m) and the wall with the door (less than 70 cm) remain.

Now to my question:

Is it theoretically possible to fit a toilet + washbasin (ideally 40 cm) on one wall? On the "right" side of the toilet, we would leave a distance of 20 cm to the wall. On the "left" side, then the washbasin with 40 cm. Is that possible?

I have to say that this bathroom is not supposed to be a guest bathroom.

Theoretically, everything is possible – comfortable reads differently. Just think of the motorhome bathrooms! I personally wouldn't have a problem putting the sink in front of a window. Nowhere does it say that the mirror has to hang above it. It could be right opposite the door and add depth. Grandma will thank you for it.