I've now discovered the potential of Google books for finding random Fitzhenry references.
Andrew Richard Fitzhenry (the son and heir of Andrew Fitzhenry of Rock, Worcester) has his obituary in the Gentleman's Magazine of 1844. It's only two lines and says:
"DERBY - March 15. Aged 36, Andrew Richard FitzHenry Esq. Late of Horn Hay."
What's interesting is that I've got his death certificate which shows that he died at 111 Great Saffron Hill, Holborn London (of consumption) on March 17th aged 35.
Ok so the date's a bit out, but what of the place? I assume that Horn Hay is the name of his estate or village, but I haven't found it yet near Derby - there is one mention of Horn Hay, but it's in Somerset.
The other interesting thing is the capital H in FitzHenry - the family may have lost the hyphen, but they haven't quite got round to putting it all into lower case.