Hello and welcome Neil,
Because you are looking to setup an aquaponics system to be self sufficient, I would advise the combination of a flood and drain bed for your fruiting plants and deep water culture beds (being your dominant number of beds) for your vegetables. Consider growing duckweed and using tilapia because the are herbivorous and feeding them with duckweed will reduce most of your feeding cost if not all.
For your mechanical filter, consider using a radial flow filter. For your bio filter, consider using K1 or K3 media. If you don’t mind the high cost, a bead filter would do the job and reduce your physical maintenance form about 30 minutes per week to 30 seconds per week. The use of a venturi in your bio filter and fish tanks are highly encouraged.
Use split flow when setting up the plumbing to ensure you reduce stress for periods you need to shut off any beds or fish tanks for maintenance or repairs. Expanding your system is also easier using split flow.
Consider keeping a small worm farm using pvc containers to make worm castings for your seed starting mix and nursery (assuming you choose to start seeds in soil or want a soilless seed starting mix) . This will also provide you with compost tea and castings you can add to your minerialization tank if you keep one.
Gravel and trays can be used for seed starting (about 400-500 seeds per tray) with water from your system.
Consider having a minerialization tank, it would be one of the best additions to your system. Outside of feeding your system, it can provide you with extra income from sales of high concentrated organic fertilizer you would be producing.
I am sure you will have so many fun moments with your friends and family building and maintaining your aquaponics system. Feel free to reach out if there is any info I can help with.
Enjoy the build of your system…