This weekend we went to check out Kew's much talked about Treetop Walkway. Being hardened London weekenders we were braced for queues, bustle and general tourist overload. It was a wonderful surprise then, to find Kew's 300 acre site a lush, garden paradise with plenty of room for all comers to amuse themselves. Even the much vaunted walkway - open just a week - was people jam free, a constant ambling stream of impressed......