there is no Registry in Peel - are you confusing with the Family History Society library ?
The only book on family history was by Janet Narasimham now in 3rd or 4th edition (see www.manxnotebook.com/famhist/genealgy/refs.htm)but Janet is I think dead, certainly no longer active in Fam His (the 1st edtion was in 1994) - the Manx Museum library@mnh.gov.im has a list of researchers - what names are you looking for ?