In reply to spartafan:
The easiest way to tell is how it feels when you're walking (although not conclusive), if it feels like a cold trickle of water they're definitely leaking, if your feet are squelching and there's puddles of water inside your boot at the end of the day they're probably leaking, if one is noticably wetter than the other then it's probably leaking. I'm not saying they're not leaking if it's not like that but there's also the possibility that it's sweat build up which is exacerbated by the outers wetting out and reducing breathability. IIRC the bridgedale rep told us that on a day's walking your feet will sweat about a coke cans worth of liquid - although reps are full of bs so who knows if that's true or not!
Having said all that you've obviously been wearing them for a while if they only have 2 months warranty left so something must have changed. Perhaps the leather is not holding the applied treatment as well as it did when it was new or maybe the GTX liner has broken down. It's hard to say without seeing them but once I've waxed my boots they keep the water out for a couple of days max (no GTX liner) before they need it again, often they're leaking a bit by the end of the day. The sport wax is good but it is quite thin, best to apply it to warm dry leather and let it soak in then buff it off and repeat with thin applications till you have built a good shiny layer up. There's quite a lot of stitching on the Merans, make sure you're pushing the wax into all the stiches and where the leather meets. An old tooth brush can be quite good for this. You might see the wax sucked into the place where the leather meets if the boots are warm and it's not been applied enough in the past. The water should bead up and roll off it for most of the day.
The other place leather boots often leak is where the sole meets the leather, the bottom of the gtx liner can also get damaged in the shoe with grit getting under the insole and combined with the sole pulling away can be an area where water gets in. Sikaflex or other PU adhesive fixes this quite well but if they're in warranty you may as well take them back.
Post edited at 08:07