The Apple iMac 27-inch is too big and if you use this then there is no need of MacBook, also the Mac mini doesn’t hit the spot. The 21.5 inch iMac is just sufficient for all your requirements. 27 inch iMac is much longer and has upgraded its game by implementing updated processors and Retina 4K display as an option.
Now let us look at the details of 21.5-inch iMac:
Initially Apple neglected to send a model which contains 4K display, but the more exciting thing is the entry level at £899 model and it is the cheapest iMac when compared to others. In this model there is no Fusion Drive, 4K display, no Magic Trackpad 2 in order to soften the blow. Instead of all these you will just get 21.5-inch Full HD display, 8GB of non-upgradeable RAM, a 1.6GHz Core i5 processor, a bog-standard 1TB hard disk, a Magic Mouse and a Magic Keyboard for just £899.
In you need to increase the speed then spend £1,049 and get 2.8GHz processor which is beefier sounding and for £1,199 you will get even faster 3.1GHz Core i5 processor along with a Retina 4K display.
In any of your iMac choice, there will be the presence of prehistoric 1TB and 5400 rpm HDD. But the hard disk is very slow. In fact after many years this is the first iMac that is sluggish straight out of the box. In the MacBook Pro the flash storage is probably spoilt, if £80 is spent, then an absolutely essential addition on the 1TB Fusion Drive upgrade can be gained. So it will be useful for you to add these additional things and make use of the advanced things, if you don’t use then you will regret for it.
If the ludicrous speed is less then there are other options to increase speed alternatively. If you just spend £160 then you will get 256GB of super fast SSD storage. If this option is not comfortable with you then there are upgrades available by which you can move up to 512GB SSD or 2TB Fusion Drive, that are available only available on the top range of Retina 4K model that will cost £1,199.
The other thing to be noticed that RAM of 21.5-inch iMac will be soldered on the motherboard and this can’t be upgraded in the future.