I have a small quantity of reclaimed 12mm solid Ash T&G. It's previously been clear spray lacquered but obviously could be painted or rubbed down and re-finished. It had been secret pinned,- now removed, so hardly any damage apart from the odd bottom groove pin hole which will cover when laid. It'd be ideal for good quality below dado panelling.
Whisper me if you're interested and I'll measure up how many linear metres etc..
I'm in N. Yorkshire.

Yes, It was originally installed on a ceiling about thirty years ago and still looks good. I have a timber store of worthwhile selected stuff like this.
I also have some quite exotic tropical T&G which I reclaimed from an office reception area when I refurbished it. It's quite dark and hard as nails, heaven knows what it is. I occasionally use bits for inlay and such, but I'll never get through it all.
The list goes on........