That's a decent price for a refurbished Mac but you can buy one for just £215 on Amazon:
https://tinyurl.com/y48ztxz4
Remember that Macs use a completely different operating system to 'normal' PCs, so you'd need to ensure that you purchased the Mac version of any software you needed, rather than the Windows version. It should be good enough for your requirement though but you need to remember that the displays on laptops can't be tweaked to precision standards in the same way that the display on a good-quality standalone monitor used with a desktop can be.
If you'd prefer a refurbished Windows machine, take a look at these:
https://www.accomputerwarehouse.com/cheap-refurbished-laptops-uk
(I'm happy to recommend that firm personally, both for the quality of their products and for their excellent customer service). One of the HP Probooks might be suitable for your needs but the HP Elitebook 840 would be better
For video processing (with Premiere Pro) you need to be looking for a decent speed CPU. Something like an Intel i7 would be great but they don't come cheap. However an i5 ought to be good enough.
You'll also need a decent-sized hard drive (or solid state drive) to store all of your videos on (unless, of course, you add on an external drive). The Mac is your link has a 128 GB solid state drive but some of the laptops in my link have bigger hard drives or solid state drives.
Video-processing also requires plenty of RAM.
My own choice would be the HP Elitebook 840. It's got a solid state drive which is bigger than the Mac's, it uses Windows (so there's a lot more free software available for it), it's got a processor speed similar to that of the Mac, it's got the same amount of RAM and it's got a slightly larger screen.
(BTW: Lightworks is far better than Premiere Pro. It's what professional film-makers use:
https://www.lwks.com/ . Many people find that the free version is adequate for their needs. It comes with a 7-day licence but that automatically renews whenever you sign in online, without limit).