Thanks for your help and hints, gentlemen.
I've oiled and ran the model in for about 20 minutes in each direction as per instructions.
Tried making a short video of my model running on DCC (ESU Lokpilot 4). Notice the random scratching sound - haven't heard that in Mike's video. https://youtu.be/1u87fvjnH3Q
Decoders I've tried so far:
Lenz Silver+ : not happy with slow running, jerky, all functions worked, moderate scratching noise
Doehler&Haas DH21A-4: very good slow speed performance, only has 4 functions so headcode boards didn't work, moderate scratching noise
ESU Lokpilot 4: acceptable slow speed performance, moderate to low scratching noise, all functions operational
At present, I'd recommend the Lokpilot albeit I normally tend to use Doehler&Haas chips. Can provide settings if it helps but still unsure whether to keep the model or not.
Kind regards
Lars