Where has all my smugness gone!

[midnightisaplace]

Ok so I thought we had managed to get past potty training. It took a very long time but by his third birthday DS was happy using the toilet and was dry at night. Maybe one night time accident in the four months after. Now, since Christmas he has wet his bed almost every night. I can't work out whats happening. He doesn't seem to be drinking any more. We have move his bedroom to a larger room but I can't see how that would make him wee the bed.
Any ideas /suggestions? We get him to go to the toilet before he goes to bed and he has a potty beside his bed.