Yep I think one of those flat triple holders might be better in the long run. The only thing is their footprint might be a bit big. I'll have to have a closer look inside my 5400.

At least with these you can replace the batteries without having to lift the holder (assuming you've velcro-ed it down). And there's also no danger of batteries slipping out if the plastic weakens. You can also get enclosed box holders (even some with on/off switches).