I have finally managed to take in all the fabulous advice and experience that has been shared here.
As for second hand/new -- I'm not too bothered either way as actually the vast majority of the equipment I use is second hand, EOS 3 itself, the 35, 50 and 135mm lenses are. In fact the only new equipment I own is the 70-200 lens and tripod! I shall keep an eye out in the classfieds for what may come along!
Reading the comments here I am inclined to try out the R3a with a 40mm lens. Spyderman, you made perfect sense and I can see how the EBL is obviously pretty important with a 75mm+ lens with that description. Certainly I use the 70-200 f/4L on my EOS 3 for portraits, but also the 135mm Takumar I have which is also f/3.5 matching the Voigtlander 90mm's aperture and I have always been pretty happy with the result. I must admit I don't actually like portraits too much where the background is completely out of focus, I like a semblance of the backdrop.
I've also looked at the fact I could get a 28/35mm mini viewfinder attachment for the R3a if I am dead set on the 35mm aspect.
I would still like to try the R2a but I think for what I am looking for the R3a will probably become quite a good option.
The older Leica's such as IIIc - IIIg aren't really an option for me, as I do want Av mode, and I don't really want to carry a light meter around. I'm not that much of a purist, but I know for what I am needing this camera for, I need it to be light and fairly no fuss, as it will get a lot of use when I am hiking and I must admit I don't want to spend too much time faffing -- if that makes sense, I need to be able to keep on the go, of course sometimes I'll go for a stroll where the slower workflow would work superbly and I would have that option. Also I am looking for versatility in the built in framelines.
Aso thanks for the advice on the grip, I can see me getting peturbed by the camera digging into me otherwise, the EOS 3 does the exact opposite where it hangs forward with anything other than the 50mm!
I am used to rangefinders in that I am always so happy when using my fairly crude but good Oly XA. I do enjoy using the camera, and I must admit that most of the time I find auto-focus more of a hinderance than a help as I never use flash, always work with available light and it gets a bit irksome when the camera is hunting! (Hence why I use MF lenses actually...)
As such so long as the camera feels right, I know I will enjoy using the rangefinder.
Hopefully I will be able to start reporting back on the choice I made and some first shots in the not too distant future as I am thinking I may dispense of the 70-200 EF lens, gorgeous kit but, it doesn't get used as much as it needs to. Especially with my Takumar 135mm being single coated, it is a lovely bit of glass for portraits...
Camera lust is such a bad thing! 🙂
Thanks everybody!
Vicky