Close behind the first misconception that you need sunshine for solar panels is that you need those panels to be fixed to your roof, that makes them need planning permission, makes them expensive to put up and virtually impossible to move.
Solar panels on the ground in your garden or around the house facing the side that gets most sunlight will only be marginally less efficient but significantly cheaper and easier to install.
Where.
Mobile generation and storage while not a turnkey “install and forget” kind of setup can be quite fun and creative, i think the main downside of it is the potential of theft since its expensive equipment you want to make sure you have the panels in a secure area where no strangers like delivery drivers have access to for example otherwise you might need to fold them away when no-one is at home.
In the UK most households have a spare car parked in the driveway that just sits there most of the time, you could safely store all the batteries in the car and have the panels on the ground around it if you have the benefit of a enclosed driveway or security cameras you trust to deter any opportunistic thief.
Otherwise a sturdy outside shed for the kit and a locked back garden should be appropriate for most cases, if you have external annexes you can get quite creative with the placement of the panels and try different setups to see which gives you the most charge.
What.
Mobile solar generation and storage equipment providers like Anker will sell you the SOLIX F2000 Solar Generator (Solar Generator 767 with 5x 200W Solar Panel) for £3700, that’s 1kW solar and 2kWh storage with a output up to 2300W, 5 year warranty and over 5000 charge cycles on the LiFePo4 battery Link
My favourite are Ecoflow who will sell you EcoFlow DELTA 2 Max + 400W Portable Solar Panel for £3319 that equals 0.8kW solar and 2kWh storage but i find it to be the superior hardware and software Link
My third favourite, Bluetti (because of atrocious customer support and weak firmware/updates) for £34446 BLUETTI AC200MAX + 3XPV350 solar panels, that equals 1kW solar and 2kWh storage Link
Any of the above is appropriate to power a flat and while heavy (all the kit will fit a small a car trunk) its mobile enough that you can move it around and experiment with placements anywhere in your garden and around your house.
Obviously is as perfectly suited to power a mobile home or your devices for a part of the day, for example you could use it to power everything in your home office for the working day or your entertainment system in the evening.
Inverters…
The above is all good until you consider you have to somehow plug everything into the battery, Ideally you will want a inverter however to feed power into your home directly so the battery plugs into the inverter and the inverter plugs into the house leaving all your house setup as it is.
Ecoflow and others will sell you a inverter unit, for example Ecoflow PowerStream 800 https://uk.ecoflow.com/products/powerstream-microinverter costs only £329 but is often sold out because its popularity
Alternatively some solar panels come with their own micro inverter that mounts under the panel, only Enphase does this https://enphase.com/en-gb/installers/microinverters
Both inverters above contain one or multiple MMPT controllers, this is what enables you to get the best of the panels no matter the weather conditions, for details https://blog.ecoflow.com/uk/what-is-mppt-solar-charge-controller/ is a recommended read.