Fitting Naim mm phono boards to Nait 3 amp?

Yes, a fairly straight forward fit.  Hardest part is opening up the case - it's different depending on whether an early Nait 3 or later one.  If the latter, you need to carefully prise out and remove the plastic pins holding the cover in place.  If no boards have been fitted before then you will need to cut the link wires underneath where each board will fit.  Failure to do this will result in a kind of motor boating effect with the sound.

If you're in any way concerned about doing it wrong or damaging the amp then I would recommend you take it in to your Naim dealer and ask them to fit the boards for you.

I have just removed the lid & taken a photo, i have sent this to my dealer to ask which specific wires to snip, fingers crossed.