Having stripped off most of the old detail I have now got effectively back to where I started! I have replaced the headcode box sandbox filler covers and TDM sockets with my own etches.  The headlight was removed and re-attached straight (Yeah I know) and the jumpers are from a Hornby 50. One thing I didn’t pick up on last time was that class 86/4 had a single body mounted lamp iron like a class 87 and not twin buffer mounted ones like a class 86/2. Not sure why I never noticed this before.