All Reviews all the time at TestFreaks UK. Amazon Discount Finder: Find hidden 75%-off deals & more. Buying from Amazon's European sites rather than Amazon UK can be cheaper.
Clever tool Priceonline.eu checks prices across Amazon's sites in France, Germany, Italy, Spain and the UK. (It also checks prices in the USA, but there you may need to pay customs, plus consumer rights vary.) The weakened pound means items might cost slightly more than they would have on Amazon EU sites, but there are still bargains to be had.