Welcome to MR, Simon_W.
MR has free ebooks that have been beautifully formatted by some very dedicated MR members. I think your BeBook uses
ePub format.
There are also lots of free ebooks at
feedbooks.com and
manybooks.net
Free and for purchase ebooks ..
smashwords.com and
baen.com Plus Baen has a
free library
You can explore using
Calibre to manage your library of DRM free books. and Kovid, the creator, frequents the dedicated
Calibre forum on MR.
Have fun in the forums and ask if you have any questions.