@eddiej;

Although the D200 is a very fine camera....it is also getting towards the end of its product cycle.
Rumors are heating up again of a replacement for it.
If you buy now, I'm afraid your timing may be similar to your experience with the D100.

My advice FWIW....take the D100 in for a sensor cleaning and wait a few more months....that should buy you some time between your wife's conservatory and the new DSLR product....everybody will be happy!

In youth, we learn....with age, we understand.