Remember there are a couple of versions of the Bryan Chapman (and even then, several variations and diversions) - normal and scenic.
Any GPS files from 2013 need to be looked at with a little bit of care due to the bridge diversion that was in place (so you don't follow the diversion which added a good 10-15 km on from memory - though there was an option to stay on the main road and miss Barmouth bridge etc. - no way was I missing that though, such an iconic view of the BCM).
To be honest, the navigation is pretty straight-forward - it'll take minutes to create your own file and know it tallies up with the current route-sheet.