Admittedly this was a Diabetes nurse, and not a dietician, but the advice that I was given was low fat, low sugar and low salt. My GP told me that I wouldn't go far wrong following the GI diet. I was also told to eat regularly, and to make sure that there is fiber-rich complex carbohydrate with each meal. Both the GP and the nurse were adamant that newly diagnosed T2s shouldn't test BG (they said that most people don't act upon test results so, at best, there is no point and at worst they cause stress and make things worse). I started off following this advice - porridge for breakfast, lots of brown rice, whole-meal bread, pasta and bananas.
I was initially skeptical about the "don't test" advice, and when I discovered this forum I rapidly became skeptical about the diet too. I have since ignored the advice on testing, and I found that the low fat/sugar/salt diet did seem to help a lot. My fasting BG was generally about 7, and two hours after eating it was usually in the 9-12 range (at diagnosis it was over 9 fasting and over 15 after a GTT). I have now bought Richard Bernstein's book and have been exerimenting with a low-ish carb diet. Without being really extreme (I don't go in for carb counting, I am just trying to avoid large quantities of overt carbohydrate), my fasting BG is usually just under 6, and during the day it rarely goes above 9 and never above 10.
In short, the "official" NHS diet helped me, but not as much as a moderate low carb diet. Metabolism is complex and everyone is different. Where I found the advice I was given really misleading is that it tried to force me into a "one size fits all" solution. What I found really infuriating is the very strong advice not to test. It is still very early days for me (I was only diagnosed a few weeks ago), but I am already quite a long way down the road to finding a diet that fits me - and it is testing that has allowed me to do this.