The issue that you have is finding a "car" style tyre with the required weight rating needed for the Bongo. At 205 you will probably struggle to find any tyres greater than the minimum weight rating 96 on 17"ers on you profile. At 225 you will probably find plenty greater than 96 but at a higher prices and higher rolling resistance! Why not compromise on 215 (as I did). I chose Sumo Firenza ST-05 215/55R17 (98load) at about £60 each which seem absolutely fine or if you can afford it Pirelli P7 XL 215/55 R17 (98 Load) at about £120 each.