I would like to replace the 670g / 1.49lb shoulder bag I use to carry my Mamiya C220f with 80/f2.8 lens around in, for something lighter and slightly smaller; without room for anything else. Preferably available in the UK or EU, and a.s.a.p., as losing that extra weight is of a matter of high priority.
I have some Mamiya TLRs, and when I want to go minimal--I use a medium-sized Zing neoprene pouch. It easily slides over the camera, only weighs a few ounces, and works well to cushion the camera with minimal extra bulk. This assumes you have a strap attached to the TLR.
A quick google found that the medium-size zings are available in the UK, also the large-size. This good news means that I won't necessarily need the car when I take the Mamiya out
I use a fairly small, reasonably light camera bag that was sold as a part of a kit with a consumer grade Canon digital SLR camera a few years ago. It has just enough room for my C330 with waist level finder, 65mm and 135 lenses, a few rolls of film, a hand meter and a couple of smaller accessories.
I've been using a Mamiya C330F for more than 25 years and although I have an ER case for it if I want to travel light I just carry a strong plastic pedal bin liner n my pocket in case it rains.