Up until about a week ago, my 7 month DS woke at least once, usually twice, a night looking for food. I figured it must be hunger cos it was never at the same time. However, after reading something on this site about the timing of the DF I decided to move the time I give the DF forward a half hour - so instead of 11pm he now gets it at 10.30pm. The first night I tried this he slept through to 6am - something he's never done in his life!!! He's done this every night since - the earliest he's woken was 5.30am. I reckon that the later DF was disturbing a deep sleep cycle which then messed up the rest of the night. I don't know if this might be helpful for your situation, but perhaps it's worth experimenting with the time of the DF before you go to more drastic measures??!!!
Apologies if you've read my account of this before - I feel like telling everyone I'm so delighted!
Good luck.
Anna x