Alternative to Vented Hot Water Tank

So in my ongoing quest to do up a rural cottage, I was wondering if anyone had any ideas on this one:

The cottage only has two places where we need hot water: The Kitchen Sink (ground floor) and the Bath/shower (1st Floor). Heating is via electric wall heaters and electricty is the only practical fuel source.

It previously had a 22.5 Gallon (yes it was that old!) vented cylinder - so about 100L, and a water header tank on the 1st floor. The water pressure was poor throughout the house.

So if we get another tank, the chances are we will have to install it on the ground floor and then use a pump to get decent water pressure to the bath/shower. This is OK, but I feel there must be a better way of doing this now - I have looked at inline water heaters, but from what I can see getting one big enough to fill a bath will not make a lot of sesne.

The cottage is going to have approx 2.5kW of Solar PV on it, is if I did use a tank, I could at least use an Eddi to heat the water in the tank when it’s sunny.

Any suggestions welcome - I’ve added some pics of the old setup (that my parents had installed in the 60s) to give you an idea of what I am up against!

If your mains water pressure and flow rate are adequate, or can be made so, then there are unvented hot water cylinders that don’t need a header tank. They do need an expansion vessel to stabilise the pressure and circulating volume, but this is much smaller than a header tank and is usually mounted with the cylinder.
Are the two hot water supplied locations close to each other as the pipe runs? If so a cylinder may be your best answer. If not your pipe losses and slowness to receive hot water where needed might require another solution.

If your hot water requirements are modest you could install individual mini-hot tanks. We stayed in a lodge which had two small water heaters, one for bathroom and one for kitchen. I can’t remember what make they were but were similar to the Ariston Andris R 15L Under Sink Water Heater. Only 15 litres, so no good it you want a deep bath!