Hi. I am using Medichecks for my blood tests currently and await the results. I found this company thru Google; there may be others. The tests aren't cheap but if you have GAD as well as c-peptide there is a discount. Yes, it's wonderful how the NHS just guesses so much and often gets it wrong; I'm an engineer by profession and realise how important proper testing is to diagnose problems. Metformin can only reduce blood sugar by 1-2 mmol and as you say is mainly of help for insulin resistant T2s. The right diet and exercise are vital. If you are young and perhaps normal or underweight then you are right to query a T2 diagnosis. If my blood tests show I have GAD anti-bodies then I expect conflict with my GP who insists I'm just another T2 and won't be happy with anything that challenges that. If my blood tests show I'm normal'ish then I will also be happy to know I am just T2 and at least know that thru a test not guesswork.