I thought I should probably follow this thread up with some thoughts and photos!!!
I ended up being offered both a Yashica Mat 124-G and a Mamiya C330f with 80mm & 55mm lens. I couldn't decide which to go for, so decided to try both!!!
A couple of months later I have put a few rolls through both of them, but not as much as I would have liked - I had been working away and weather up & down. However, using both I think I will still keep both of them.
The Yashica is small and light, enough so that I had on my shoulder whilst in London last weeknd without any issue - I also find it faster/easier to use and reasonable results from my first roll through it!! I haven't put a battery in it so can't comment on the built in meter. When I first got the pair, I found the focusing screen to be brighter and easier to assess fine focus than the C330. After cleaning the C330 screen it was better, but I still think I find critical focusing on the Yashica a little easier.
The Mamiya..........what a piece of kit!! I love it's heft, the build, the bellows focusing. Initially, I couldn't work out how to fire the shutter.....I had to resort to the manual before realising the various lockouts present to prevent accidental exposure!! It certainly convinces you that it has the minerals to take a quality photograph!! I do find it slower to use than the Yashica, but the range of lenses and closer bellows focusing gives me something the Yashica doesn't have. Sadly, the first roll I had developed was rubbish. I'm not 100% sure what has gone wrong, in my haste to test the camera out, I used it on a day with some very poor conditions - it was very overcast, thick dull sky, misty and rainy!! So I don't really know if the resulting images were due to the poor conditions, me or the lenses - but I have another roll ready to develop to give it a second look. I have also just bought a 180mm Super - gives a lovely 'headshot' perspective and I'm looking forward to seeing the results!! It does make the C330 a little awkward to handhold at close focus though!!
So here are some results...my first rolls through a fully manual camera (apart from my Holga), I was quite happy with the results of the Yashica - I even managed an accidental double exposure! Two of them are very underexposed, but I realised I had misread my shutter speed after I took them!! Both are Portra 400.
https://adobe.ly/2ELitJv
And here are the rather poor results from the Mamiya - I am putting these firmly down to my own errors, but the next roll will confirm I'm sure!!
https://adobe.ly/2EIa89e
I have a roll of Tri-X ready to develop from the C330f - so will be interesting to see what I get second time around!!