Haverford House does not exist but is based on several large houses in the north of England, as well as a house that exists only in my head. The grounds and lake at Haverford, however, are based upon the estate at Nostell Priory near Wakefield in West Yorkshire. There has never been a mystery of a missing lady’s maid at Nostell so far as I know, but there was a scandal over some unpaid-for Chippendale furniture.
The smooth-bellied toad, like the blue-crested hoopoe in Midsomer Murders, is entirely make-believe.