Leonora (1544) was a Richard Debenham 'Surf Scoter' design (c.1963), the hull being completed by my father Barry Mourant, her first owner.

Can anyone (e.g. Tony Lane) provide any history from previous MR yearbooks on its ownership/whereabouts after it parted company with my father?

Richard. I'll see what I can find tomorrow. I have to go down the pub now.

1544 'Leonora'. The first change of ownership recorded is in the 1970 year book.
The new owner was J.R. Halton, Flat 6, 39 Colville Gardens, London W11 and Tamesis Club.
The 73 book shows a change of address to B.J.N.Ltd, Berger House, Berkeley Sq, London W1.
The 1975 yb shows the owner as C.R. Brocklehurst, 16 Amersham Rd, High Wycombe, Bucks again at Tamesis. By 1976 he/she had moved to Upper Thames SC.
The 1978 and 79 books shows no owner but the 1980 yb records the owner as P. Lidgley, 15 Amersham Hill Gardens, High Wycombe, Bucks. Club unknown. 
I regret no further changes are recorded in succeeding year books. It might be worth enquiring of Upper Thames, Cookham and Tamesis whether they have records of Lidgley as a member in the 80s or of 'Leonora' in their dinghy parks in ater years.

Thank you Tony that's helpful.  I'll investigate some more with the info you've provided.