Thanks for the information. Very useful comments.
Decision made!!!
I have decided to stay with my Nikon D700 for the following reasons;
The D700 is a real workhorse. Always wanted one and I have had this since about 10,000 shutter count (now nearly 30,000). Always been looked after and I ‘understand’ it. Yes it’s heavy but there is a reason for that - it’s solid and tough!
I use a Voigtländer 20mm on the D700 which is a very small lens. This actually makes the setup quite comfortable to handle - not front heavy and unbalanced. Replacing with the Fuji I will end up with a bigger lens for a wide angle setup.
Glass. Replacing glass is expensive. I have 3 lenses for the D700. Two of them good ones. I’d have to start again and unfortunately no money tree in the garden.
I have numerous batteries, memory cards and filters for my current camera and lenses. Replacing those also comes at a cost.
Hiring one as mentioned above is probably a better plan as mentioned above to see how the camera and in particular the electronic viewfinder works for me. A different option may also to have a fixed lens camera for street photography such as the X100F. I (well it was my wife’s) had a small Ricoh years ago and used it all the time.
Lets face it, we all just love cameras!