Hi Shurm.
Welcome to the forum. What Totsy has said is spot on. You should have been given time of around three months to try and control things with the diet and exercise. It isn't 'old hat', it is in the latest NICE guidelines regarding prescribing and treatment of T2 Diabetic's. (2009)
However, I don't have access to all your medical records, so there may be a very good reason to start you on a low dose of Metformin to try and help get the numbers under control. Your readings aren't the only things that the GP will consider. As for Metformin being for life....no it isn't. I was on the maximum dose of 3g for a long time and then got it down to none after getting better control of my Bg levels. So it is not a 'given.'
If taking a few pills get's you lower numbers quickly, where is the problem ? At my worst I was 'popping' 23 pills a day......now down to just a few, non diabetic related ones. Sometimes, the odd pill can help you achieve your goals quicker, then aim to get off them asap. Not such a big deal really ?
edited.
Clearviews too has underlined what can happen.