I remember a British Gas trailer on u-tube explaining how their apprentices do NVQ3 in one year.
Armourer's situation, offers a different angle, where he already had technical know how, and ability to self learn, inquire and work out technical information - so he already had a skill-set and could transfer this to plumbing. However, I would think he had many head-scratching moments in the early days.
The facts are that NVQs assess 'competency' against standards and provided you meet the assessment standard, this is good enough for the qualification - whether you consider qualifications to reflect 'real' competence at work is another matter.
Hence, you could argue to go straight into NVQ3, if the college refuses, then get legal aid and sue them. Or go to your MP and explain how the college system has excluded you from achieving you aims.
This said, I do not disagree with the comments made so far. When we talk of NVQs and getting a qualification, we are not really talking about being able to do the job in reality, which is concerned with 'competence' not 'competency' - for competence at work, you will need to be guided over several years in the work place, depending on your attitude, existing skill-set, and determination.
My advice would be to get any job, and steer well clear of this industry, which really has been exploited by the training providers and colleges, which claim to serve our communties.