My lovely, comfy Exped Downmat 7 has a slow leak, the last couple of times I've used it it's been almost flat by morning.
There are no obvious holes, there is no dirt in the valve. I've just spent a happy afternoon trying to trace the leak in my sisters bathtub (I've only got a shower) but could see no trails of bubbles even when applying pressure.
Can anyone suggest a way to find the leak before I put Expeds 5 year warranty to the test ? (bought through Wiggle)