Finally finished the brake line replacement using Venhill Lines in a blue colour - and what a job it was.
Filling the lines meant that I could finally see whether splitting the calipers had been a mistake....
Fortunately it wasn't. No problems with everything fluid-tight and working as it should.
Details, including the torque settings used are here towards end of video:
https://youtu.be/QdGetkNbxcwHope this is helpful
Dave