No, don't buy a complete kit, buy the stuff you actually need - and there's a price premium for the complete kits, justified by inclusion of things like an overpriced and unnecessary flight bag.
There are two commonly used sets of books in the UK: Pooleys (originally written by Trevor Thom, then re-written by Peter Godwin) and AFE (written by Jeremy Pratt). Both are good, personally I regard the AFE books as better to learn from, and the Pooleys books as better for sources of reference. There is also an excellent, and much cheaper online course from CATS here:
https://www.catsaviation.com/courses/ppl.html . Why do CATS basically give this away?, as a loss leader for their core business professional pilot courses: take advantage, they want you to.
If buying the books, the only one that changes significantly between editions is aviation law - everything else buy old copies on eBay and save yourself a lot of money. Similarly, an old second hand chart, right now, is fine for study purposes, and any flight planning equipment again, no harm in saving money by buying secondhand. But do have the latest air law book, whichever set you're using. The chart you want for study is almost certainly the CAA 1:500,000 VFR chart - they're about £16 new, many people will have old ones they don't want.
The "Flight Computer" that you'll need to learn, is known in the USA as an "E6B", and once you know that you'll find loads of online teaching material / YouTube videos / simulators, etc. that you can use as learning material. Don't get hung up on the subtle difference between models - they all work the same.
If you know what aeroplane type you will be learning on, then you should be able to find online manuals, for them - or ask on here and somebody will have a scanned copy.
Best of luck, it's a great journey.
G