Let me share my story to you hope it will give you an idea.
I graduated Bachelor of Science in Commerce - Major in Accounting it was assessed here in the UK by NARIC (National Recognition Information Centre for the United Kingdom) their assessment : It is comparable to Certificate of Higher education (CertHE), falls between N/SVQ levels 3 and 4. I'm glad it is recognised.
Thing is when I started looking for job in accounts most of the companies requires AAT for jobs like Payables/Receivables/Accounts Assistant etc and also requiring software (i.e. Sage Line 50, SAP, TAS etc).
The question is that why go down to level 2 when you nearly finished 4? (which the ECO said you have abandoned) WHY NOT? the fundamental is the same but there is a bit of a difference and the College will never stop you taking Level 2 even if you have done it before.
I am currently doing Level 2 NVQ in Accounting the fact that I have a degree in Accounts from the Philippines. If you are allowed to appeal try to explain your circumstances why you opted not to finish your studies that time give them reason which you think is acceptable and the fact that you wanted to do it again here in the UK means to say that you've seen the benefit of having a qualification. Although ECO won't see it that way (He probably will think why UK and not Phils?), they will always presume you want to enter UK to work using student visa.
When I enrolled I was given the choice which level I want to start , the choices were 2 3 and 4. I chose 2 means to say they will never say no you cant do 2 coz you already done 3 or 4. You can always go one level down if you wish to and it will benefit you because it will give you a fresh start and familiarity (UK style).
Hope everything will be ok for you. Best Regards.