Excellent -- so it's a 1958 build : one of the 1/149s that was 'cylinders in use' or one of the 1958/59 last Pressed Steel 1/146 batches some of which were also..? (The pre-1/149 1/146s that were built 'cylinders in use' had spindle buffers, according to David Larkin's 'Middle Era' book, and yours look like self-contained...)
Good stuff as ever though.
--
John