I thought the chip would fit in the tank area, but it soon became apparent that I would need to remove some of the boiler, and associated weight, to get sufficient space above the wheels. The cab area was the backup and I initially decided that I could stick it to the motor with some of the double sticky foam that comes with the chip. This proved to be too obtrusive; the chip and foam were very visible astride the motor.
By then, I'd wired the chip in as per instructions and it became apparent that the wires were sufficiently stiff to carry the chip. I therefore removed the foam and allowed the chip to float free. By tweaking the wires, the chip sits snugly inside the roof area and is substantially less visible. As recommended, I insulated the inside of the body against potential shorts; sellotape worked fine for this.
If I were building the N8 now, I'd allow space to mount the chip in the tanks. The result I have is the best, I think for a loco not built with DCC in mind. Here, with the help of my daughter, are my first tentative steps into DCC;
I'll post some close-ups of the loco in the next day or so.