...she seems overtired all the time. If I put her down when she looks tired I find I can barely get her to bf and have solids before it is time to go back to bed again and she doesn't necessarily eat well because she is not that hungry. On the days where I have tried to keep her up longer in order to get a bf and solids in I find I have a lot of trouble putting her to bed and the day gets even more messed up!!!
I think this is the part of your question I don't quite understand. It seems in your routine that you are indeed bf and having meals before naps, but are you saying that keeping her up to feed the solids is making her too tired? If so, have you tried feeding the solids a little sooner? My dd actually started straight off with solids followed by bottle. You can do it what ever way suits your dd best. You don't necessarily have to wait 1-1.5 hrs after bf'ing.
2 hrs of A time is typical at 6 months, but if you feel that is making her too tired, then you should definitely shorten it. A confusing thing though is that short naps at this age also means the A time is too short. However, if she is clearly showing tired signs, but still takes a short nap, then you'll need to use pu/pd or some other resettling technique to put her back to sleep. You will need to do this for both naps and for at least 40 minutes or until the next feed time.
I encourage you to follow Tracy's guidance in the book. You have picked an excellent reference for your situation. Also, we have a forum dedicated to Nightwakings (
https://babywhispererforums.com/index.php?board=33.0), and one to Naps (
https://babywhispererforums.com/index.php?board=30.0) in case you have to opportunity to visit those for further assistance.