Heron [Co Down] family trees exist in the Blackwood Family history manuscript trees in LinenHall library, Belfast. The Volume references are 23p1 Greenfield, 25, 29, 31, 42T, 45, 75, 86 Reid.
I suggest you ask them for photocopying estimates if they think your knowledge relevant and be prepared to pay the extra for post and packing. However if the material is really relevant when you get it, I suggest a further donation to this unique library that is always needing extra funds. Linen Hall Library,17 Donegall Square North, Belfast BT15GB, Northern Ireland, Telephone: +44 (0)28 9032 1707, Fax: +44 (0)28 9043 8586, Email:info[at]linenhall.com.
Good hunting Jim