Yes bral, but you are allowed to make an approach irrespective of RVR's provided you do not go below 1,000' ARTE/4d/OM or equivelent if they are still below your minima. Of course, it's a valid question as to why you would want to commence an approach with 300m RVR when you need 550m....unless you plan to circle.
So if Circ minima is 1,100 agl (highish for circling) you could theoretically commence an approach, level off before the approach ban altitude and circle.
Legal? - theoretically yes. Sensible? Open to debate depending upon numerous other factors.
A4