yeah, i'm with throckenholt, quite relaxed abotu wet beds, both my older 2 have them now and then. In fact DD (3) has had three in the last 2 weeks but that's quite a lot for her. It's OK tho. DS was wet yesterday mornign (he's 5) so I was a bit disappointed but glad I still have the undersheet on!
Can you leave the bathroom light on so he can easily find it in the night? Also try no juice (esp Ribena) after 4pm, lots of other drinks tho; sorry if you have read that thought from me elsewhere.
Am sending you thoughts of the Gobi desert, Saudi Arabia (no rivers there IIRC) etc