Rob,
I would personally advise buying the equipment in stages, and buying it, as you will need it. Things to save till later on in your training include a kneeboard, an aircraft checklist, a logbook and a headset (in fact, I didn’t buy a headset until I’d actually passed my PPL!)
If you cannot wait to buy at least some of the goodies on offer, then I would suggest starting off with buying a 1:500000 chart covering the area in which you will be training (there are three areas to choose from). Study everything on the chart – noting the airspace around your chosen training establishment. Look for any nearby controlled airspace, and attempt to fathom out how it all works. Buy some china-graph pencils or marker pens so that you can write on your chart. You will need to draw lines on your chart when you begin your navigation studying – and if you have already bought the books as a precursor to flight training – then you can get on with this straight away.