I've had the book for a couple of weeks now. I decided to make a few dishes and give an honest opinion on the results. I made the base, a Madras, a Vindaloo, pilau, naan, and CTM.
The base was easily the most time-consuming I have ever made. I made it completely to spec with the single exception being that I did not have asafoetida on hand. I would appreciate thoughts from others on how important (or not) this ingredient is. I made the bhaji oil per spec, as well as the garlic/ginger paste, tomato paste, tandoori marinade, and vindaloo paste. The lack of a true specific measurement system made the whole process more challenging than usual. I realize that BIR chefs do not measure teaspoons, veg weight, etc, but I would have preferred more specific measurements than the dipping system, although its certainly more true to BIR practice.
The base took forever to cook. I used the full-size recipe in a large stockpot. Cooking on lowest heat, meant that the base never got to boil. I had to crank it up to start the simmer process and then put it back to lowest heat. After the first hour, it was clear to me that the veg was not yet fully cooked. It took close to another hour for the veg to be sufficiently cooked. After blitzing and adding water, it took about an hour longer than specified for the oil to separate - but it did separate and give me a finished base that wasn't unlike the many bases I have made from CR0. So far so good, just a little (a lot) time consuming.
Madras - the Madras was good. I personally do not think the tandoori masala belongs in this dish. Its part of the tomato paste, the dipping, and I used the optional step of adding a little tandoori marinade (again without a measurement recommendation to go by). A decent Madras for sure, but too much tandoori masala for my taste.
Vindaloo - I made the Vindaloo paste, but strangely enough I can't see anywhere in the book where its used in a main dish.

I took a flyer and decided to add the Vindaloo paste to the Vindaloo dish. In my opinion, a Vindaloo should have more differentiation from the Madras beyond just heat level. The Vindaloo paste provides this. I used about a chef's spoon (again had no measurement to go by). This was by far my favourite dish, but again the tandoori masala did not belong.
Pilau - it was OK, but not as good as the usual pilau I use (Bruce Edwards original - not 2nd edition - pilau recipe).
Naan - the naan was actually pretty decent, and close to the formulation I use. I used my own method for cooking the finished naan.
Chicken Tikka - the tikka marinade was similar to many others I've tried from this site. There are better tikka recipes available here IMO.
CTM - I can see why the author didn't consider it a curry, as this one uses no base. It was a reasonably tasty dish, but it was not IMO a CTM I've had from a BIR before. I actually thought the pureed sultanas and fruit cocktail had a very nice taste. I might consider adding some of this to my usual CTM and see how it tastes. This recipe needed curry base.
Will I use these recipes going forward? Probably not. I think my usual Madras and CTM are better than these recipes. I may adopt the Vindaloo paste, as a way to differentiate the Vindaloo from a hotter Madras. The base is too time-consuming. CA's, Razors, BE etc all produce equal or better curries. The book itself was worth the buy, and the dipping system is most likely spot on BIR practice. An interesting and worthwhile experiment overall.
-- Josh