Index Ventures, a London- and San Francisco-headquartered venture capital firm that primarily invests in Europe and the U.S., recently announced its latest partner. Carlos Gonzalez-Cadenas, currently COO of London-based fintech GoCardless and previously the chief product officer of Skyscanner, will join Index in January. Gonzalez-Cadenas is a seasoned entrepreneur and operator, but has also become a prolific angel investor in the U.K. and Europe over the last three years, making more than 50 angel investments in total. Well-regarded by founders and co-investors, his transition to a full-time role in venture…