So I've decided to go for the Multiplus 12/800/35, with a pair of 180Ah Gel batteries in parallel. This meets the budget and should cover us for 4hrs.
I was informed by the battery seller that a 35A charger would be insufficient, which I'm not clear about. If the batteries should not exceed 50% DoD, then we'd only need to recharge 180A correct? This should take slightly more than 5hrs if I understand the way this works.
The person also stated that I'd need 25mm cables, not 35mm ones. Again, I don't know if it's important
(side note, I've now wandered off my own topic, no longer going for the Growatt/Pylontech combo. oops)