This search result looked promising... "UK", specifically mentioned the voucher, and is an official google adwords website, with a .co.uk extension...
UK – Get £75 in ad credit when you spend £25 - Google AdWords
https://adwords.google.co.uk/intl/en/home/
Except, the page doesn't mention the voucher, mentions a $10 credit and displays the US phone number... So not the right country or currency or content. But apart from that, spot on. I remember the days when google was a good search engine, and we used it because it gave us goods results... showing my age now...