I found that using my shaker was a bit rubbish to be honest and I found that they sometimes got bits in them. Which aren't nice. I would recommend using an electronic whisker (which is what I normally use, when there is one). Especially if you haven't done a diet like this before, you don't want to be put off by the lumps.
Also I would recommend putting some ice in the freezer ready for you shakes - these are much better with ice - I think.
If you don't like the choc or vanilla ones, you might find it useful to plonk some coffee in for a Mocha or Vanilla Latte .
Keep us updated with how you get on. I have my first weigh in tomorrow. The last 7 days have been okay and I'd say the worst of it was probably the headaches, and some partial hunger. Keep drinking water and keep motivated!
This is how I did it too. I added three sweetners, some vanilla essence and a teaspoon of Fibre Clear. I lived on vanilla and soup! The ken wood smoothie maker was brilliant, no lumps and a filling milk shake