Yeah I had the same thing happen but that was after I had downloaded Wipeout. I followed these instructions to get back to the Store page and was able to get LBP no sweat. I checked out the movies as well but they are garbage, not worth the download. Other regions seemed to get a much better choice of movies!
http://blog.eu.playstation.com/2011/06/03/welcome-back-content-is-available-now-frequently-asked-que...Q: I no longer have the option to choose my free Welcome Back games. What can I do?A: If you navigate away from the Welcome Back section of the store without choosing your free games or exit the store completely you may need to follow the below in order to choose and download your free games.
On your PlayStation 3 or PlayStation Portable navigate to the PlayStation Network icon on the XMB
Log into your PlayStation Network account and choose Account Management > Transaction Management > Services List
Choose “PlayStation Network Promotions” from the list of services displayed
Select either “PS3 Free Games” or “PSP Free Games” and then choose “Select Content”
You will be taken to the store to choose your remaining free games.
Although, Burnout Paradise and James Pond are a nice freebie for PSN+ members.
Also Streets of Rage 2! Classic!