Mish, have you worked with a registered dietician and/or certified diabetes educator? Most insurers will cover at least one visit (sometimes more) with a diabetes diagnosis. Doctors often just throw some general guidelines at you, but RDs can provide much more tailored advice.

ETA: oops, just noticed you're in the UK, not sure what the insurance coverage is there. But even if you have to pay for it yourself, it could be very worthwhile.