I think we could bring this down further!
If like most people all you need is an Apple Watch to look fancy, tell the time, pay for stuff and track your steps then a £50 Apple Watch Sport is a nice shout. It still looks the business and does the basics. It fits all sorts of great third party straps from Amazon for an extra tenner.
Computer? Apples software support is really good with 90% of basic needs still being supported on much, much older hardware. An i7, 16gb ram, 128SSD/500HDD combo drive Mac Mini will set you back £125 and run High Sierra like a dream. Peripherals can be scrounged from anywhere really or just use an old TV for a 26” monitor.
IPhone? An iPhone XR has a good camera, mod cons like FaceID and can be had fin good condition for £225.
iPad? The 8th gen iPad is still great for your portable needs and will probably mean you don’t use the Mac Mini as much. This can be had for £240.
That’s about £700 all-in. Prices are from UK 2nd hand retailer Cex that offers a 2 year warrantee on all goods too which is something you won’t get buying from eBay or Apple refurb.