mean to say you're doubting C.H., Keith?
It does sound a tad vague to say simply C19? - perhaps we should consult the receptionist in future - you should persuade her to join the GMB. Still the main thing is you've supported a worthy cause;-)
my opinions are ……………….. the decoration looks to be pteridomania - which is more likely to imply second half C19, though not an infallible guide - S. & F. contains shed loads of glass with this type of decoration, and the book dates to around 1880 from memory. Also looks to be wheel engraved and not etched - does that sound about right. Is there a pontil scar - depression or whatever - can't see clearly from the pix.
Bet you wish you hadn't asked