anchor.diff:  
               ! Initialise HDF5 and open file.
               ! NOTE: if file exists, then it is overwritten.
  +!REVIEW-AJWT: But the get_unique_filename above ensures this doesn't happen?
               call h5open_f(ierr)
               call h5fcreate_f(restart_file, H5F_ACC_TRUNC_F, file_id, ierr)
   
  +!REVIEW-AJWT: I don't immediately see what these are used for.
  +!REVIEW-AJWT:  These kinds are used in the write_* functions.
               ! i0 kind?  What a nice interface!
               h5_i0 = h5kind_to_type(i0, H5_INTEGER_KIND)
               h5_p = h5kind_to_type(p, H5_REAL_KIND)
               h5_lint = h5kind_to_type(lint, H5_INTEGER_KIND)
   
  +!REVIEW-AJWT:  This is getting a bit cryptic (but ok if you bear with it)
               ! --- metadata group ---
               call h5gcreate_f(file_id, gmetadata, group_id, ierr)
               call h5gopen_f(file_id, gmetadata, group_id, ierr)
   
                   call write_string(group_id, dhande, VCS_VERSION)
   
  +!REVIEW-AJWT: This doesn't appear to agree with the comments at the top
                   call write_string(group_id, duuid, GLOBAL_UUID)
   
                   call date_and_time(values=date_time)
  +!REVIEW-AJWT:  What does this actually look like?
                   write (date_str,'(2(i0.2,":"),i0.2,1X,2(i0.2,"/"),i4)') date_time(5:7), date_time(3:1:-1)
                   call write_string(group_id, ddate, date_str)
   
  
positive.code: 
                  call read_integer(group_id, dcalc, calc_type_restart)
  
                  ! Different calc types are either not compatible or require
                  ! hyperslabs (fewer particle types) or require copying (more
                  ! particle types).
  
negative.code: 
          end subroutine read_integer
  
  !REVIEW-AJWT:  I feel the frisson of data overflow and horrible bugs for the future in this code.
  !               Perhaps at least a length check?
          subroutine read_ptr(id, dset, dtype, arr_ptr)
  
              ! Read an array from an open HDF5 file/group.
  