Thanks everybody for your advice - it looks like the interference suppressors are my problem, although as I have already said, earlier Bachmann decoders (and dare I say it, Hornby TTS decoders) don’t appear to be effected by them.
As I don’t want to dismantle the Atlantic’s tender again for fear of damaging it ( I’ve already damaged the handrails as I’ve had it apart several times already) I’ll experiment with another loco when I’ve got the time.
Thanks again.
until