Andy, you're probably fine with the whole "two-cheeses-in-one" thing. I'm not sure of the effect of the water at that stage, but the extra time was short enough that it doesn't seem like it will make a HUGE difference in something like over-acidification etc. (Just talking off the top of my head here, I'm certainly not the expert, but I've had situations with various cheeses that resemble yours in general upshot, and they've all turned out okay/not very different.) At worst, you may have some extra mechanical openings because of the odd pressing - if that bothers you (I don't mind 'em myself).
GlennK, I don't know what happened to your "failed" cheddar (why did it fail?), but if you still have it, stick it in the back of the cave somewhere, or even in your fridge, and forget about it for a year or so - you'll be surprised at how yummy that extra time will make a "fail"!