Most of my purchases have been from Modelsport unless there's something not in stock. I've used King's Lynn models to order an RC buggy that was out of stock and surprisingly was cheaper than Modelsport but that's not a local store or anything, I'm completely the other side of the country being NW based. I just like Modelsport's website, it's by far the easiest to navigate around especially if you want spares and upgrades.
I got 2 decent lipo batteries from eBay that came as a pair and I've been happy with those and I've just ordered a new drive shaft on eBay as well, mostly because of the free delivery. Even if the price is inflated on eBay it's still often cheaper than paying delivery charges of £4 for a £3 item.
I'm completely cutting back on Amazon unless absolutely necessary, far too much money gets frittered away on Amazon.