So, I put on two new kegs on the weekend. Run some perc through the lines and taps. Replaced washers on the two taps that had the original washers with the thicker ones. I only replaced the washers, without disassembling the rest of the tap. Adjusted the tension so that the auto-close would just start to stick, then backed off a tiny bit until it would close. Run some clean water through, hooked up the new kegs and immediately heard hissing from both taps as the air in the lines was escaping. I run about half a glass of beer through each tap and waited about a minute. Both taps were slowly seeping beer. I tightened both taps until the seeping was not obvious and tried pouring more beer. Both taps were still working with auto-close, but without obvious leaks. I'm not sure if the pressure in the taps or the cold taps help, but auto-close seems to work slightly better when the taps are "in-circuit" as opposed to without load.
Checked for seeping the next day. One tap had evidence of slight seepage, the other one seemed fine. I tightened the seeping tap and the auto-close works about 80% of the time. It seems to be sensitive to how I pull on the tap handle. Straight pull seems fine, any slight sideways pressure on the handle causes it to stick.
I'm coming to the conclusion that the Intertaps with new washers are fine, but the auto-close mechanism is fiddly and lets the whole thing down. Maybe stronger springs would help. I think the Intertaps will probably be fine taps, as long as they manage to sort out these early product issues and fine tune their future production runs.