The filesize is hardly a problem as it's only 4MB
And it's not slow in the slightest, everything happens instantly.
Redesigning the switchboard has proved pretty easy using the new Nagivational Control in Access 2010, it's now looking pretty snazzy and with a few more queries/features.
If I was starting it from scratch then I'd possible be more inclined to go with a design like that, but given that everything works 100% as intended and I've already got a lot of data in it (as does my gf in her version of it), it would take way too much data entry to fill everything in, when the amount of detail in there at the moment is just right