OTC...
Doziles are exactly the same as restavits, they both contain 25mg of Doxylamine Succinate, restavits are a little cheaper though (Doziles are a pretty little clear purple Temazepam-like gel-cap)
I definitely agree with superbabydoc. Although, when serious insomnia has hit me in the past (doesn't now), i've found, short-term, that prescription sedatives work better, there's no hangover, as there can be with anithistamines. I've only been prescribed 10mg Temazepam, and they're only very short-acting (2hrs) so really, they induce sleep, but don't "keep" you asleep like other heavier benzos, ie Mogadon, etc. If you are having trouble sleeping at all, then perhaps ask for something longer-acting. Personally, i find herbal sedatives haven't worked for me when i REALLY couldn't sleep (no doubt to do with my mind-set), but as a relaxant, herbals are quite good. I've not needed help sleeping for a long time now, but Doziles have really "come to the rescue" when i've occasionally needed them.
*edit* Just wanted to add that i've heard of quite a few people taking meds like Mersyndol, Dolased, etc to help sleep. These meds also contain smaller doeses of Doxylamine Succinate, as well as codeine and paracetamol. Paracetamol is quite bad for you at high doses and codeine can cause quite serious constipation, as well as be habit-forming. So, if you're really wanting to get something OTC, go for the doziles et. all, as you're only getting the one ingredient. It's also interesting to note, that through chatting with some friends who still indulge regularly in recreational substances and choose OTC sedatives as a sleep-aid, some chemists are requiring that you provide ID to purchase them...

sorry for the ramble...