I just had a quick look at the battery you mention @Oscarmax and from what I have read it sounds good. Ticks all the boxes for latest standards ECT. I am sure you would be fine with his battery. I have no idea on costs comparisons though. Having said that, just looked and wow! Do you have someone to install for you ?
The latest Solax Triple batteries are now made by LG, the company that fitted my solar panels in March came out yesterday and have quoted me a price fitted £4,426.09 including VAT. It would have cost £800 less if I had purchased the master battery online plus I would have required an electrician to set up and wire it all in, however if I wish to add another slave battery in the future it is just a simple plug and play
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.