I understand that as a holder of a full car license I don't need a license to drive a moped in Switzerland. Do any of you guys know what exactly differentiates a "moped" from a motorbike in this instance. Is it the engine CC?

49cc I think is the limit. Do you understand German? www.stva.zh.ch has all that information.

No I don't speak much German, not enough to understand that site anyway. Maybe it's about time I got myself a proper motorbike license anyway. 50cc is a bit too small.

A moped or mofa (motorised bicycle) has pedals, is allowed to drive 30 km/h and has a yellow license plate with no emblems.

can someone confirm that i do indeed need a motorbike license if I am going to get myself anything larger than 49 cc ?

You do indeed.