CP420 Part 2 Chapter 15: Clearances, Issue 3, 10th March 2017 (Electricity North West document); contains diagrams validating PL16 D2S and naming L3 DS, as well as outlines for NWE PL1; sadly none of the drawings state or depict the full towers and cannot be used as a basis for diagrams here.
Development Near Lines
National Grid: Development Near Lines (Planning & amenity aspects of high voltage transmission lines and substations), revised October 2001
Hinkley Point C Connection Project: Design Drawings 132kV Overhead Lines (May 2014), covering wooden pole 132 kV, L4m, L7(c) DT, L8c, L12 and T pylons. Amusingly this National Grid document uses the term “pylon” instead of “tower” throughout.
The “Tower Bible” is set of Central Electricity Authority (Eastern Division) tower plans compiled into a PDF by Jon Bruford to enable easy identification of tower types. The original plans were drawn between August and December 1956. Covered in the Tower Bible are PL1, PL1a, PL4, PL7, PL16 and L16. Drawing numbers for PL2 DT and for single-circuit PL1, PL1a, PL2 and PL16 and for L2 and L3 are given but these drawings were not included. Also missing are the pages for less common types such as PL1a DX and gantries.
Uprating of Overhead Lines, Roshan Bhattarai B.E. M.Tech., Cardiff University PhD thesis, 2011 (includes tower design designations for L132, L2, L3, L4 and L7 giving the conductor and earthwire types)
Wires Pipes Pylons
A publication subtitled “Guide to landowners and their advisers”, published in 1962. See limited subset of pages on Flickr. This document contains slightly distorted diagrams of L2, L3, L6 and L132 straight line towers.