Not sure if your Northern Ireland or Eire ...
Ulster Society for Prevention of Cruelty to Animals
28 Benvardin Road
Tel: 08000 280010
The Irish Blue Cross
15A Goldenbridge Industrial Estate, Inchicore, Dublin 8
Tel: 01 4163030
Last Hope Animal Charity
PO Box 56 , Navan, Co.Meath
Tel: 085-7172024 / 087-6920777
Bit of a mish-mash but I guess if you contact one they'd be able to point you in the right direction - my guess is the bird is a Harris Hawk - cant find any recorded details of them attacking cats but Id share your concerns Heaven only knows where your neighbour bought /obtained the poor thing but you aer absolutely right that a rabbit hutch is no place for it..... Good luck and keep us posted ....