we also found more sleep didn't = more sleep. Very annoying! We began cutting her sleeps down around 10 months. At first it was limiting how long she slept for. I found that worked. She didn't sleep more than an hour. Then when she started staying up later again, we cut out a sleep. By the time she was around 18 months she wasn't having a day sleep at home at all. Even now she only has a sleep at creche and that's because all the other kids are... At hme she only has a day sleep if she's unwell or been swimming. She WILL sleep in the car at any given chance... even if it's first thing in the morning!

SO, have you tried cutting down the length of the sleep?