Just to update the thread, I opted for a Ricoh GXR with 24-72mm sensor module in the end for a number of reasons, among them price, the famous ricoh snap mode, and dipping my toe in the ricoh waters. I hope for the gxr and 24-72 to give me a taste of everything a GRD 3/ 4 would have offered, but in the more flexible flavour of a short zoom instead of the 28mm fixed GRD view. I also plan to see if I potentially could get on with just a 28mm in the future, as well as tasting the GXR and considering some of the other modules before they disappear.
Thanks for all the thoughts and feesback, and should have the camera some time next week most likely, to see how it fits the bill 🙂