To audible sighs of relief, the hottest British summer in living memory finally gave way for the opening day of this year’s Thames Traditional Boat Festival. But there was sunshine enough to catch the varnish on a glittering array of traditional boats, many on display on the grassy bank, others parading up and down this famous part of the Thames…a group of Amphicars, a fleet of Starcraft, the Dunkirk Little Ships, Her Majesty’s rowbarge Gloriana, slipper craft, Bluebird K3, old steam boats, each having a moment in the spotlight amid snatches of approving commentary. “The kind of boat we like, and the kind of family we like,” was a favourite. Ashore, the stands of classic boats (some cars too) stretched for miles, with builders showing o. their newest (or oldest,…