Stephen Freeman
As you will know there are several photos in David Smiths Book, featuring Brent, as to what the relevant switch and crossings were used depends to a large degree on the period being modelled and the location on the line. Anything on the branch and yard is likely to be of pre- Grouping design, whilst the mainline was probably renewed to the newer standards, especially as some the track outside the station is known to have been added during the second World war.
Brent itself has had several models built of it though not of absolute accuracy (if that was ever possible) as has Kingsbridge.