Managed to get my brakes working last night, so I can now stop as well as go!
I really hadn't been looking forward to bleeding the system, and was having nightmares about spending days pumping the pedal, but it couldn't have been easier!
I went for the squirting-fluid-into-the-callipers-with-a-syringe approach. A few squirts into each one in turn, tried the pedal and it was pressurised
Usually takes me several hours to get any pedal pressure!