From what I can work out, I've only been able to add two species in the last 9 months - here's my final list, unless I remember anything else:
Hagley Falconry Centre 31/1/15
1. Red-tailed hawk
2. Snowy owl
3. African spotted eagle owl
4. Brown wood owl
5. Ruppell’s griffon vulture
6. Barn owl
7. Burrowing owl
8. Northern hawk-owl
9. Northern goshawk
10. African fish eagle
11. Southern crested caracara
12. Himalayan griffon vulture
13. Turkey vulture
14. Eurasian eagle-owl
15. Golden eagle
16. White-headed vulture
17. Chaco owl
18. Long-eared owl
19. Bengal eagle owl
20. Striated caracara
21. Common Buzzard
Dudley Zoo 10/2/15
22. Great grey owl
Cotswold Falconry 17/2/15
23. African pygmy falcon
24. Ferruginous pygmy owl
25. Bateleur eagle
26. Bald eagle
27. Tawny eagle
28. Lanner falcon
29. Black-chested buzzard eagle
30. Aplomado falcon
31. Great horned owl
32. Common kestrel
33. Saker falcon
34. White-backed vulture
35. Hooded vulture
36. Red-footed falcon
37. Ferruginous hawk
38. Swainson’s hawk
39. Yellow-headed caracara
40. Chimango caracara
41. Boobook owl
42. Common scops owl
43. Indian scops owl
44. Woodford’s owl
45. Western screech owl
46. Southern white-faced scops owl
47. Ashy-faced owl
48. Barred owl
49. Vermiculated owl
50. Verraux’s eagle-owl
51. Oriental bay owl
52. Ural owl
53. Mottled owl
54. White-eyed kestrel
55. Mountain caracara
56. Secretary bird
57. American black vulture
58. Gymnogene
59. Yellow-billed kite
60. Palm nut vulture
Cotswold Wildlife Park 17/2/15
61. Northern white-faced scops owl
Raptor foundation 19/2/15
62. Northern hobby
63. Tawny owl
64. Short-eared owl
65. Crested serpent eagle
66. Brahminy kite
67. Marsh harrier
68. Magellan horned owl
69. Little owl
70. American kestrel
British Wildlife Centre 22/2/15:
71. Peregrine Falcon
Huxley’s Bird of Prey Experience 22/2/15:
72. Northern crested caracara
73. Spectacled owl
74. Honey buzzard
75. Steppe eagle
76. Gyrfalcon
77. Red kite
78. Laggar falcon
Eagle heights 22/2/15:
79. Griffon vulture
80. Steller’s sea eagle
81. Martial eagle
World Owl Trust 10/3/15
82. Brown fish owl
83. Tengmalm’s owl
84. Desert eagle owl
85. Forest eagle owl
86. Sunda scops owl
87. Tropical screech owl
88. Cape eagle owl
South Lakes Safari Zoo 10/3/15
89. King vulture
Lotherton Hall 26/7/15
90. Andean Condor
Chester Zoo 11/11/15
91. Luzon Lowland scops owl