I took your advice Mecce & contacted my Licensing Department today, who wouldn't go into any further detail as to the refusal but proceeded to tell me as long as my circumstances remained the same (no change to medical history & no further Police interaction) if I re-applied in 12-15 months they'd be no reason to oppose a second application, They also stated that in the meantime there's no reason why I can't use other peoples weapons (within the constraints of Firearms legislation) if I want to shoot.
Whilst somewhat frustrating I don't have any urgent need to be in possession of