I think you are confusing a fasting BG test with a glucose tolerance test (GTT). You don't need any glucose for a fasting test - you just take a blood sample in the morning, before eating. All diabetics should do this regularly to monitor their condition (I would suggest more than once a month, although if the condition is well under control, it doesn't need to be that often).
A GTT is used to diagnose diabetes, not to monitor it. If you do want to do a GTT yourself - then you need about 75g glucose, to provide a sufficient hit. If you can't get lucozade, then you can buy glucose tablets in pharmacists, or glucose powder from health food shops (body builders sometimes use it). Failing that, you should be able to get a similar result using sugar.
However, I strongly suggest that you shouldn't do this! A one-off GTT at the time of diagnosis is fairly harmless, but you really don't want to do this regularly (avoiding this sort of glucose hit is the most important part of any diabetes control diet). Also, it wouldn't tell you anything useful. It would tell you that you still have diabetes, but trust me on this - if you have been diagnosed with diabetes then you still have it!