Hi, just wanted to report that the swap from the older amr1173 (silver box - GEMS) to the newer AMR5700 (blackbox-THOR) has worked out great for me.
My cc was working only intermittently so I built with a good friend with better soldering equipment and much more experience, an adaptor like the one described in the link:
https://ejcruz.smugmug.com/Other/Range-Rover-P38/
We even copied the idea of cutting the box ;-) better a good copy than a bad innovation ...
The new(er) ECU just fits exactly where the old one was located and there's plenty of space for the adaptor behind the dash.
It switches much smoother, than the old one (at least as mine did, IF it was working).
Just make sure You get one matched for Your engine / car. There are four versions circulating around: Disco V8 4.0 and 4.6, Range 4.0 and 4.6 and a setting, which I do not know, called "default". Got this information from a diagnostic manufacturers website and it is approved by a few articles in other forums. The used parts dealer always try to sell You, what they have stating the part number counts ...
So if You suspect Your ECU to be the reason for strange behaviour (or none) of Your cc, give it a try. The AMR5700 are really cheap to get and a working cc is worth the effort.
If You can not solder, find a good old friend who likes drinking whisky as much, as Yourself ... let's talk about maximising reasons to cheer / toast ;-)
As the ECU is fitted to the RR Classic and Discovery 1 it might work there as well, as described in the link.