By Amber Murray Pest-control company Rentokil has reported an uptick in revenue as it grapples with the after-effects of a profit warning and activist investor backlash. The firm told markets this morning that revenue grew by 3.6 per cent year on year in the three months to 30 September, from £1.39bn to £1.44bn. Its North American arm reported revenue growth of 1.4 per cent year on year, with Europe up 4.7 per cent and Asia up 6.5 per cent. However, currency headwinds curbed overall revenue. Growth at actual exchange rates was flat year on year, at £1.38bn. Last month, Rentokil shares plunged …