I just wanted to pass on my experiences to you Mums with younger babies. When my LO was about 3 months old she started taking 45 minute naps. I drove myself nearly crazy trying to get her back to sleep, followed advice on here and in the BW book. In the end, after about a month I decided to give up and go with the flow.
I just put her down for a nap when she was tired, she'd sleep for 45 mins and then we'd start again - it wasn't always EAS but we were both happy. She wasn't tired and I wasn't frustrated. We settled into a routine of 4 lots of 30-45 minute naps per day that continued until she was about 6-7 months old, when she moved to one am and one pm nap.
All the way through she continued to sleep through the night, we followed all the other BW guidance to the letter but I stopped concerning myself about the naps.
We're now 8.5 months old and she's started taking 1.5 hour naps in the afternoons again. Without any PU/PD or worry on my part.
Please, please don't do what I did and beat yourself up because you haven't got a perfect 4-hour or 3-hour EASY. It'll all work out in the end. I'd also advise you to look at page 201 of Tracy's book "The Baby Whisperer solves all your problems" - Tracy herself says that not all babies need long naps.
Better go - she's just waking from her lovely long snooze. Your baby will get there too, in the end, but you won't do them any favours by getting yourself in a tizzy in the meantime!
Heather