OK have now looked closer and inspected this under microscope.
Have played it into the computer on some program that works out notes, and when holding it as was told (side with air button in right hand) and pressing top middle button on RHS it comes up as a G, if hold microphone to other side it seems to be a C, does that sound right?
Also am getting other notes off other buttons, A,D and F* does this seem correct?
Other thing I have noticed now I have looked closer is that what I thought was an entwined C and J is in fact a G and J!
Have also found more writing on side of handle, another entwined G and J, screwed notes, Deft Ance, London Make.
Have looked at the broken button closer and it actually comes out, it has a little hole in the middle of button, could it just be a lost screw?
Also the leather bits are 'well used' and a very slight split where it joins the wood, obviously I will have to edit my listing on ebay as this poss will cause a leak I guess?
Thanks again for everyone's comments and suggestions, I want to be as honest as possible in my listing of this, am probabaly gonna end up under selling it, but at least then I have no come back, have been totally open about being a dummy with regards to the instrument.