I haven't read the whole thread by a long way, so just a couple of things:
The IMC Confuser is great. Make sure you get at least 90% on it.
I don't like TT Book 5 very much. It is very confusing and (not having looked at it for a few years) I could swear there are (were) some diagrams to do with VOR/NDB tracking which were simply wrong. The book appears to be the work of several different authors. But it will do for the IMCR exam, because the CAA exams are written to fit the content and terminology of the TT books (or perhaps the other way around).
I am positively the last person to knock the IMCR (which is a super privilege to have) and will always have a go at those old farts who say it's a "get into trouble rating" etc, but -
If you are doing the IMCR to go places, rather than just a piece of paper, it helps a lot to have an instructor who actually flies for real. Otherwise, one can get an idea that instrument flight is just a load of NDB holds, more NDB holds, and perhaps an ILS at the end. The reality, even just pottering about the UK, can be substantially different. There is a lot more to know if one is going to use it for real; e.g. navigation using GPS/VOR/DME and how to get decent en-route weather data.
The above isn't a criticism of the Rating or its content; it is a criticism of the way it is generally taught. Every instrument instructor should have a current IR and should be using it, too.