i have the exact same noise on my petrol FR.. recently had the cambelt changed as well so dont think its related to that
i took it to the garage that did the cambelt and they said its probably the alternator bearing (the thing in the centre of the frame during the beginning of the video)
these engines make all sorts of weird noises.. clicking from the injectors, strange tin-y rattling, an almost diesel-like idle
anyway i doubt its something major.. my rattle comes and goes, ive noticed its worst when climbing a steep hill at low revs