The aeroplane may have been Cat IIIa capable but only if it was equipped with HGS. Besides, it is highly unlikely this operator was 'approved' by the Authorities to conduct Cat IIIa approaches even if they had the equipment.
Certainly, if it were so equipped, the crew trained, the company approved and on a Cat II runway, they should NOT have missed the first approach in the first place.
Something out of place with this one I'd say.