Yes this is what I was looking for!
41000 clients... will cat <file> | sort | uniq
and get results:
Apple iPad,00:14:10
Apple iPad,00:92:C3
Apple iPad,00:9D:13
Apple iPad,00:E0:4C
Apple iPad,04:54:53
Apple iPad,10:40:F3
Apple iPad,10:93:E9
Apple iPad,14:10:9F
Apple iPad,18:20:32
Apple iPad,1C:AB:A7
Apple iPad,28:6A:BA
Apple iPad,28:E7:CF
Apple iPad,34:51:C9
Apple iPad,34:C0:59
Apple iPad,40:30:04
Apple iPad,40:B3:95
Apple iPad,44:2A:60
Apple iPad,48:02:2A
Apple iPad,4C:B1:99
Apple iPad,54:26:96
Apple iPad,5C:96:9D
Apple iPad,64:20:0C
Apple iPad,64:A3:CB
Apple iPad,64:E6:82
Apple iPad,70:73:CB
Apple iPad,70:DE:E2
Apple iPad,74:E1:B6
Apple iPad,74:E2:F5
Apple iPad,78:CA:39
Apple iPad,7C:6D:62
Apple iPad,7C:C3:A1
Apple iPad,84:29:99
Apple iPad,84:85:06
Apple iPad,88:53:95
Apple iPad,8C:2D:AA
Apple iPad,8C:7B:9D
Apple iPad,8C:FA:BA
Apple iPad,90:84:0D
Apple iPad,98:B8:E3
Apple iPad,98:FE:94
Apple iPad,9C:04:EB
Apple iPad,A4:67:06
Apple iPad,A4:D1:D2
Apple iPad,B0:65:BD
Apple iPad,B4:F0:AB
Apple iPad,B8:C7:5D
Apple iPad,B8:F6:B1
Apple iPad,B8:FF:61
Apple iPad,BC:3B:AF
Apple iPad,BC:67:78
Apple iPad,C4:2C:03
Apple iPad,C8:BC:C8
Apple iPad,D0:23:DB
Apple iPad,D8:00:4D
Apple iPad,D8:30:62
Apple iPad,D8:A2:5E
Apple iPad,E0:2A:82
Apple iPad,E0:B9:BA
Apple iPad,E0:F8:47
Apple iPad,E4:8B:7F
Apple iPad,E8:06:88
Apple iPad,EC:85:2F
Apple iPad,F0:D1:A9
Apple iPad,F4:1B:A1
Apple iPad,FC:25:3F
Apple iPhone,00:1B:63
Apple iPhone,00:1C:B3
Apple iPhone,00:1D:4F
Apple iPhone,00:1E:52
Apple iPhone,00:1E:C2
Apple iPhone,00:1F:5B
Apple iPhone,00:1F:F3
Apple iPhone,00:21:E9
Apple iPhone,00:22:41
Apple iPhone,00:23:12
Apple iPhone,00:23:32
Apple iPhone,00:23:6C
Apple iPhone,00:23:DF
Apple iPhone,00:24:36
Apple iPhone,00:25:00
Apple iPhone,00:25:4B
Apple iPhone,00:25:BC
Apple iPhone,00:26:08
Apple iPhone,00:26:4A
Apple iPhone,00:26:B0
Apple iPhone,00:26:BB
Apple iPhone,00:88:65
Apple iPhone,00:C6:10
Apple iPhone,00:F4:B9
Apple iPhone,04:0C:CE
Apple iPhone,04:1E:64
Apple iPhone,04:54:53
Apple iPhone,04:F7:E4
Apple iPhone,0C:74:C2
Apple iPhone,0C:77:1A
Apple iPhone,10:40:F3
Apple iPhone,10:93:E9
Apple iPhone,10:9A:DD
Apple iPhone,14:10:9F
Apple iPhone,14:5A:05
Apple iPhone,14:8F:C6
Apple iPhone,18:20:32
Apple iPhone,18:34:51
Apple iPhone,18:9E:FC
Apple iPhone,18:E7:F4
Apple iPhone,1C:AB:A7
Apple iPhone,20:C9:D0
Apple iPhone,24:AB:81
Apple iPhone,28:37:37
Apple iPhone,28:6A:BA
Apple iPhone,28:CF:DA
Apple iPhone,28:E0:2C
Apple iPhone,28:E7:CF
Apple iPhone,28:EF:01
Apple iPhone,30:F7:C5
Apple iPhone,34:15:9E
Apple iPhone,34:51:C9
Apple iPhone,34:C0:59
Apple iPhone,3C:D0:F8
Apple iPhone,40:30:04
Apple iPhone,40:A6:D9
Apple iPhone,40:B3:95
Apple iPhone,40:D3:2D
Apple iPhone,44:2A:60
Apple iPhone,44:4C:0C
Apple iPhone,44:D8:84
Apple iPhone,46:4C:0C
Apple iPhone,48:02:2A
Apple iPhone,48:60:BC
Apple iPhone,4C:B1:99
Apple iPhone,50:EA:D6
Apple iPhone,54:26:96
Apple iPhone,58:1F:AA
Apple iPhone,58:55:CA
Apple iPhone,58:67:1A
Apple iPhone,58:B0:35
Apple iPhone,5C:59:48
Apple iPhone,5C:95:AE
Apple iPhone,5C:96:9D
Apple iPhone,60:33:4B
Apple iPhone,60:C5:47
Apple iPhone,60:FA:CD
Apple iPhone,60:FB:42
Apple iPhone,64:20:0C
Apple iPhone,64:80:99
Apple iPhone,64:A3:CB
Apple iPhone,64:B9:E8
Apple iPhone,64:E6:82
Apple iPhone,68:09:27
Apple iPhone,68:96:7B
Apple iPhone,68:A8:6D
Apple iPhone,6C:3E:6D
Apple iPhone,6C:C2:6B
Apple iPhone,70:56:81
Apple iPhone,70:73:CB
Apple iPhone,70:DE:E2
Apple iPhone,74:E1:B6
Apple iPhone,74:E2:F5
Apple iPhone,78:A3:E4
Apple iPhone,78:CA:39
Apple iPhone,7C:11:BE
Apple iPhone,7C:6D:62
Apple iPhone,7C:C3:A1
Apple iPhone,7C:C5:37
Apple iPhone,7C:D1:C3
Apple iPhone,84:29:99
Apple iPhone,84:85:06
Apple iPhone,84:FC:FE
Apple iPhone,88:53:95
Apple iPhone,88:C6:63
Apple iPhone,8C:2D:AA
Apple iPhone,8C:58:77
Apple iPhone,8C:7B:9D
Apple iPhone,8C:FA:BA
Apple iPhone,90:27:E4
Apple iPhone,90:84:0D
Apple iPhone,98:03:D8
Apple iPhone,98:B8:E3
Apple iPhone,98:D6:BB
Apple iPhone,98:FE:94
Apple iPhone,9C:04:EB
Apple iPhone,9C:20:7B
Apple iPhone,A4:67:06
Apple iPhone,A4:D1:D2
Apple iPhone,A8:96:8A
Apple iPhone,A8:FA:D8
Apple iPhone,B0:65:BD
Apple iPhone,B4:F0:AB
Apple iPhone,B8:17:C2
Apple iPhone,B8:8D:12
Apple iPhone,B8:C7:5D
Apple iPhone,B8:F6:B1
Apple iPhone,B8:FF:61
Apple iPhone,BC:3B:AF
Apple iPhone,BC:52:B7
Apple iPhone,BC:67:78
Apple iPhone,C0:9F:42
Apple iPhone,C4:2C:03
Apple iPhone,C8:33:4B
Apple iPhone,C8:BC:C8
Apple iPhone,CC:08:E0
Apple iPhone,D0:23:DB
Apple iPhone,D4:9A:20
Apple iPhone,D8:00:4D
Apple iPhone,D8:30:62
Apple iPhone,D8:9E:3F
Apple iPhone,D8:A2:5E
Apple iPhone,D8:D1:CB
Apple iPhone,DC:2B:61
Apple iPhone,E0:B9:BA
Apple iPhone,E0:C9:7A
Apple iPhone,E0:CB:1D
Apple iPhone,E0:F8:47
Apple iPhone,E4:8B:7F
Apple iPhone,E4:CE:8F
Apple iPhone,E8:06:88
Apple iPhone,EC:85:2F
Apple iPhone,F0:4F:7C
Apple iPhone,F0:A2:25
Apple iPhone,F0:B4:79
Apple iPhone,F0:CB:A1
Apple iPhone,F0:D1:A9
Apple iPhone,F0:DC:E2
Apple iPhone,F4:AC:C1
Apple iPhone,F8:1E:DF
Apple iPhone,FC:25:3F
Apple iPod,00:1D:4F
Apple iPod,00:1E:52
Apple iPod,00:1E:C2
Apple iPod,00:22:41
Apple iPod,00:23:32
Apple iPod,00:23:DF
Apple iPod,00:24:36
Apple iPod,00:25:00
Apple iPod,00:25:4B
Apple iPod,00:25:BC
Apple iPod,00:26:08
Apple iPod,00:26:4A
Apple iPod,00:26:B0
Apple iPod,00:26:BB
Apple iPod,00:88:65
Apple iPod,00:C6:10
Apple iPod,04:1E:64
Apple iPod,14:10:9F
Apple iPod,14:5A:05
Apple iPod,14:8F:C6
Apple iPod,18:E7:F4
Apple iPod,28:37:37
Apple iPod,34:15:9E
Apple iPod,40:D3:2D
Apple iPod,44:D8:84
Apple iPod,58:55:CA
Apple iPod,58:B0:35
Apple iPod,5C:59:48
Apple iPod,60:33:4B
Apple iPod,60:FB:42
Apple iPod,64:B9:E8
Apple iPod,70:56:81
Apple iPod,70:73:CB
Apple iPod,7C:6D:62
Apple iPod,7C:C5:37
Apple iPod,88:C6:63
Apple iPod,8C:2D:AA
Apple iPod,8C:7B:9D
Apple iPod,90:27:E4
Apple iPod,90:84:0D
Apple iPod,98:D6:BB
Apple iPod,B8:C7:5D
Apple iPod,B8:F6:B1
Apple iPod,BC:67:78
Apple iPod,C4:2C:03
Apple iPod,D4:9A:20
Apple iPod,D8:30:62
Apple iPod,D8:A2:5E
Apple iPod,E8:06:88
Apple iPod,F0:B4:79
Apple iPod,F4:1B:A1
Apple iPod,F8:1E:DF
iPhone,28:E0:2C
iPhone,58:1F:AA
iPhone,98:D6:BB
iPod,18:E7:F4
I'm then using this to put into our windows 2012 server DHCP into a policy to give lower lease times, I'm using a power shell command:
set-dhcpserver4policy -Name "Apple iPad" -Condition OR -mac EQ,001410*,0092C3* etc...