The international infrastructure group, Balfour Beatty, has agreed the sale of a 23.9% interest in the Edinburgh Royal Infirmary PPP concession and of its entire 50% interest in the Aberdeen Waste Water PPP concession.They are both to funds managed by AMP Capital Investors Limited, the Australian wealth management company, for an aggregate consideration of £24.3 million. Balfour Beatty will re…..