If you have not seen Bealieu, then certainly go and see London. I saw both, but only due to circumstance and friends and availabilty.
And I bought both brochures, hence the comparative thoughts.
Bealieu is afterall a purpose built (sort of), in situ car museum. London, being London, really won't have the space to showcase LALD parachutes and the like as part of the themed locomotion of Bond. And there is a lovely brasserie just opposite that serves the most wonderful coffees.
As for what is not present, I couldn't say. That said, various things-Skyfall that were Not present in Bealieu are now present in London.