https://tepeo.com/thezeb
take a look a this.
Not a recommendation , just a possible thing to look at.
Im guessing this has got sunamp kit in it

Couple of people on this forum have sunamp kit.
it would be interesting to get their latest view on it.

FIrstly though priority is to reduce your heat load.
spend money on that rather than fancy expensive kit to create heat or store it.
You'll struggle to produce enough energy from the PV to cover heat demand even if you do reduce it significantly
thats just the reality of when its sunny and when you need heating


DamonHD is a great investigator of such thing https://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html

turns out he edit an update 2 days ago

We have PV & 2x SunAmps for hot water, though our heating is provided by panel heaters since our space heating demand is v. low.

General experience was that as 'early adopters', buying directly through the company was a complete nightmare and for various reasons we ended up with no hot water for several months while everything got sorted out.

However, the landscape has changed a lot in the intervening 4 years and I think both the product and the company has improved somewhat. Even back then there was a plumbing option to branch off and do space heating as well as hot water, so I definitely think this is feasible - at the end of the day it's just a heat store in the same was as a cylinder is.

There are two critical considerations. The first of these is control systems - ours uses a MyEnergi Eddi to divert excess solar into the SunAmps and then puts the rest into the grid once they're full. This kit isn't designed specifically for SunAmp, so the Eddi thinks it is talking to a standard hot water cylinder element, but this can be compensated for and the Eddi has generally been very reliable. There may be other diverters available, but I'd recommend reading up on whatever you choose, because this is what you will be interfacing with most of the time as the SunAmp is effectively a dumb white box. Very robust and reliable, but completely opaque in every sense.

The second issue to think about is sizing. We have two SunAmp batteries, a 3kWh and a 6kWh and if I could change anything in our build it would be to upgrade the 3kWh to a larger size. It really only holds enough for 1 warm shower, which was a risk to my marriage for a good few months until we sorted out the charging cycle. Ultimately we've ended up running the smaller battery on a regular overnight boost so that we can be sure it has enough charge to be full. When we used to run it off the PV excess there was a risk even in the summer time that the water would run out too quickly. I hate suggesting oversizing things as that runs counter to the ethos of this forum, but in this case you really do want a margin of error in your tank size and you can always 'part-fill' (unlike with a normal hot water cylinder).