A new version of my e-book Britdata is available here (£9.99) and on Leanpub (US$11.99 plus VAT). I have updated it with the recently-released population estimates from the Office for National Statistics, as well as information on how GDPR affects subject access requests.
Whether on Leanpub or direct, buyers automatically get updated versions when they come out – I have just sent this new edition to those who had already purchased it – and it comes with a 45-day money-back guarantee. To give you an idea, you can read the introduction here and the list of contents here.