Quantum certainly do not rate very highly on Product Review.
We had a Saxon heat pump at our previous residence which was fantastic but unfortunately they went out of business.
Here is an article regarding heat pumps which includes Reclaim which offers a stainless steel tank model.
And some other models with stainless steel tanks.
https://www.sanden-hot-water.com.au/how-a-sanden-heat-pump-system-works
A stainless steel tank system does not need a sacrificial anode which must be regularly replaced to avoid the tank being destroyed by corrosion.
