I agree with Marcellus.
When MJ was about 8mths old she was eating dinner at about 4.30... Gradually it has been pushed back by sleep times and snacks as she has gotten older, but most days we have dinner (all together) at 5.30pm.
finished before 6pm, straight in the bath, out at 6.20-6.45 (depends on how she is in the bath) change, read in her bed room, feed and then bed. Most nights she is in bed between 7pm and 8pm depends on the day and her day sleeps.
I still dont walk out of the room until MJ is asleep... sometimes i am in with her for a while. I take her cues though, sometimes she wants me to sit there quietly next to her, other days she wants patting and singing... Sometimes she crys before sleep and she ususally always crys when she wakes.
Winding down didnt always work with us too - sometimes she seems to get more and more hyper... basically this was when she was tired - the more they are tired the more they seem to jump around and get excited.
Honestly you little one sounds very similar to how MJ was... she never slept longer than 45 mins and honestly i felt like i must be doing it all wrong cos everyone else seem to have a good sleeper and then there was us (maybe we were just the honest ones thou!!!)
The other thing i started to do was pre empt the sleep sycle, so for a week i would creep into MJ's room and sit next to the cot, as soon as she stirred i would pat and shush and she usually went straight into the next cycle. I did this when she dropped to one sleep and was still only haveing a 45min nap - after a week, i could stay out of the room, but was nearby in case she did waken - i would quickly go in, and try and resettle.
Sometimes she would try and get up and it would take a bit of settling, but i KNEW that she was still tired and needed more sleep and so perservered - but if she got really upset i stopped.
Dont know if any of these things will hel[.
But it sounds pretty normal to me - and yes it does get better, but it takes time
