The serial number scratched into the casing is c and s 189050
When opened there is a brass plate to the right with Knauss Coblenz Cegrundet 1832 with two coin-like sigils. The one on the left looks a bit like a roman emperor and the one to the right is a lady with a spear and a wreath with a bird in the foreground.
To the left of that is a large brass plate with two coats of arms. The left one is the crest of the kingdom of Wurtemberg and the one to the right is two rampant crowned griffins supporting a shield with a diagonal stripe
The piano has a plate under the keyboard protector indicating that it was sold by William r Swan 328 oxford road opp Royal infirmary Manchester
As far as I can tell it doesn't have any other markings on it. Any help or advice you can give me would be appreciated. I'm not interested in selling it I'd just love to know the history
The coin-like pictures indicate exhibition medals, see
Knauss is a fairly well-known maker, "Gegrundet" means they were established in 1832, but no reliable dates are available for their serial numbers, so even if you look around and find other numbers, they will not help. The piano was made after the dates of the medals, if you can read those, but you have little hope of finding out the history of the individual piano.
Your best hope of a date is, if your tuner feels it is safe to remove the action (the working parts of the notes) it may be marked with the action makers' name and number, and I may be able to date that.
If you can post photos to show what the WHOLE piano looks like, unobscured by dogs, stools, vases etc., I may be able to tell you more.
Email via my website.
If you find old references or links on this site to pianogen.org, they should refer to pianohistory.info