I have experience of selling Nad and also know the Solo well (I,ve sold
2 this week).You would not be down-grading going to the solo as it is
excellent.It will have a slightly less warm sound but maybe slightly
more punchy compared to your NAD.Any dealer worth their salt would not
mind you taking your kit to them for a direct comparison though which
is always the best thing to do.Some may even let you try it at home.

Thanks guys - I thought the lack of responses might be due to not
having heard both side by side, so not to worry.
And yep, I'll be checking out both in my local hifi shop. Promising to
know that they should at least be in the same league.

Nick