Hi again. Yes I am using Hornby track, and it is on a baseboard, albeit glued down and not pinned. I'm pretty sure that my issues are related to the track not being 'perfect', since the locos do seem very sensitive to any slight track deviation resulting in derailments of the front bogie wheels. Despite dropper wires at reasonably frequent intervals, these track discrepancies are seemingly enough to disrupt power and therefore BT. I reckon it's going to have to be a track lift, get everything perfect on the baseboard, and then relay the track, this time perhaps pinning it down rather than gluing it with PVA.