The excellent Taunton Trains website has a set of photos taken in late 1987 showing the signal box being removed from the lineside and transported away in two sections to its new home at the Coleford Railway Museum in the Forest of Dean, Gloucestershire. Go onto the main Taunton Trains site and look first at the Memories section then under the sub-heading 'Big Change' which deals with the 1980s resignalling project. The box has been fully restored in original GWR colours and is now plated up as 'Coleford Junction Signal Box'. I shall make a visit later this year and report back.
Here are a couple of 'from the window' shots of the site of the 'box taken from a slow-moving HST on the down Bristol line in August 2017, note the access gate in the railway boundary fence (just visible in Norman's picture), the WW2 concrete pillbox and the former signalman's 'privy' still in-situ to the left of the site where the signal box formerly stood, also 'Saturn Bridge' on the adjoining canal.
With best regards, Guy Vincent