A while ago put myself on the diet from Dr Michael Mosley's book 'The Fast 800', which uses Meal Replacement Shakes, diet bars, and a low calorie, low carb meal
Yes it worked but it got a bit boring and in any case he doesn't recommending using this for months on end
I used Exante products - the milk powder ones were OK, if a bit sweet; the vegan ones tasted awful
When I made up the powder in the shaker jar I added a spoonful of natural yogurt to reduce the sweetness, and that also made them a bit thicker
Once you start Searching t'Net you'll find several brands, and you can also find them in supermarkets, chemists like Boots & Superdrug, and even bargain/discount stores.
Slimfast is common, but you usually have to search around in odd corners, right on the bottom shelves, or ask the staff for any of these powders.
Depending on the supermarket I have found them in the ladies cosmetics section, World Foods, and next to the dried milk & sports drinks
I notice that shops often have a Slimfast starter kit or week's supply pack at reduced prices; but I also notice that some of the meal recipes in their leaflets include spuds or pasta because they're for weight loss, and not specifically diabetic, so adjust accordingly
I've mixed up the various powders & products from different makers and don't seem to have suffered any problems
They are mostly based on milk powder or soya protein isolate, or sometimes the vegan ones use finely milled soya and other flours
To this basic powder the makers add vitamins & minerals, flavours and sometimes sweetener
As far as I can tell the composition is similar, and they are all much of a muchness
They work as long as you follow the advice
Some of the prices are a bit high, for example Exante cup soups were expensive and not very nice, so I just use ordinary cup a soups and pop a multivitamin tablet now & again
Look out for offers in the shops, and once you've made an initial purchase from Exante you'll get offers, besides the reductions mentioned by ColinUK
There are YouTube videos but I haven't watched them all by any means
I'd say just try a few, check your sugars and see how you get on
Something I did find, which is obvious when you think about it, was that I had a couple of mild hypos in the afternoons, brought on by the reduction in carbs and food in general, so be aware of that; check your bg & have sweets handy
And remember, they're a means to an end, they're not meant to be a fantastic culinary experience