Welcome to the party, I am sure there will be many questions, and everyone on the forum will do their best to help answer these.
I first got into e-bikes, and years later came here and joined the off-grid world. My experiance with the small cells is these are better suited to high-current things like ebikes, and less so for stationary systems like off-grid power. I have made a dozen or so small cell batteries for e-bikes, lawn mowers, kids-ride-on-toys, portable power station, etc. but for stationary power, in the capacity that makes sense for off-grid, prismatic LiFePO4 cells are my recommendation. These can be purchased as cells alone, and you assemble them into what you need. Typically 8S for "24" volt, and 16S for "48" volt. Do your own research and compare costs of cells per 100Ahr of capacity and # of cycles you will get from each, and you will see why the prismatic cells work. Cells are available in many sizes (capacity) such as 50Ahr, 100Ahr, 160Ahr, and (my favourite) 280Ahr capacity. Since you are comfortable with the idea of DIY battery, the cells will be no problem to build yourself.
I don't see a location shown, however from the 240V inverter you posted, you are perhaps in UK or EU somewhere using 240V primary power. If you can indicate approximately location, it can assit us with recommendations. Planning to keep the equipment in a shed suggests a warm-ish climate, at least we hope so, since the equipment and batteries require certain temperatures to function properly.
Generally, it would be recommended you begin with a list of loads you wish to power, what these require running, what they will consume in 24 hours, and any high in-rush currents (motors) so you can then design the system to suit.
A starting budget may be a good point, to assist with suggestions.
I am a big supporter of a modular system, that will allow you a low cost entry point into solar/PV be easily expandable, and allow you to do all the work yourself so you save expense, and learn as you go.
