If the callsign is say BE9TV is it being used for that particular flight next day or for another route at another time which would explain callsigns being repeated
Well taking the first flight on my list, BEE13Y, here are the 62 instances from my log since the beginning of the summer seaon, showing first/last times and altitudes:
BEE13Y 28/03/2010 08:35:18 08:57:16 20575' 3275'
BEE13Y 29/03/2010 08:28:29 08:52:00 22650' 5150'
BEE13Y 31/03/2010 08:13:19 08:43:33 18350' 3975'
BEE13Y 01/04/2010 08:03:36 08:23:14 19600' 5425'
BEE13Y 03/04/2010 08:15:50 08:33:14 16875' 3900'
BEE13Y 04/04/2010 08:17:53 08:39:45 22850' 3800'
BEE13Y 05/04/2010 08:05:48 08:27:26 20200' 3225'
BEE13Y 06/04/2010 08:13:44 08:34:08 22425' 4375'
BEE13Y 07/04/2010 08:06:01 08:28:53 22900' 4600'
BEE13Y 08/04/2010 07:57:48 08:22:41 22650' 4275'
BEE13Y 09/04/2010 08:01:08 08:26:03 18850' 3100'
BEE13Y 11/04/2010 08:09:17 08:34:25 20325' 2850'
BEE13Y 12/04/2010 08:10:21 08:35:33 15000' 2750'
BEE13Y 22/04/2010 08:03:32 08:16:00 20300' 14400'
BEE13Y 25/04/2010 08:25:54 08:54:05 21550' 2875'
BEE13Y 26/04/2010 08:06:16 08:29:06 15000' 4275'
BEE13Y 27/04/2010 08:16:18 08:34:01 19650' 3700'
BEE13Y 28/04/2010 08:07:32 08:28:03 21625' 3625'
BEE13Y 29/04/2010 08:18:26 08:40:16 21400' 2900'
BEE13Y 30/04/2010 08:07:14 08:33:16 22300' 5650'
BEE13Y 01/05/2010 08:06:03 08:26:08 23425' 5400'
BEE13Y 04/05/2010 08:04:18 08:27:54 22125' 13600'
BEE13Y 07/05/2010 08:13:55 08:31:03 18450' 10225'
BEE13Y 15/05/2010 08:11:01 08:27:25 16000' 5775'
BEE13Y 16/05/2010 08:20:55 08:40:43 19975' 3800'
BEE13Y 19/05/2010 08:03:22 08:29:10 18550' 4650'
BEE13Y 20/05/2010 08:15:13 08:38:20 15200' 3400'
BEE13Y 22/05/2010 08:14:49 08:43:33 17175' 2525'
BEE13Y 23/05/2010 08:09:12 08:36:53 25000' 1675'
BEE13Y 25/05/2010 08:05:35 08:28:57 19375' 3125'
BEE13Y 26/05/2010 07:58:51 08:34:56 18600' 8950'
BEE13Y 27/05/2010 08:05:28 08:33:46 19250' 3625'
BEE13Y 28/05/2010 08:05:09 08:30:36 20975' 3950'
BEE13Y 29/05/2010 08:05:53 08:31:00 20650' 3300'
BEE13Y 30/05/2010 08:00:16 08:23:24 23600' 3250'
BEE13Y 31/05/2010 08:10:36 08:30:38 19500' 2900'
BEE13Y 01/06/2010 08:08:59 08:28:06 21400' 1600'
BEE13Y 02/06/2010 08:23:07 08:47:04 22575' 6475'
BEE13Y 04/06/2010 08:12:21 08:39:11 15375' 1225'
BEE13Y 06/06/2010 08:17:27 08:37:20 15400' 3025'
BEE13Y 08/06/2010 08:09:07 08:38:14 15200' 1750'
BEE13Y 09/06/2010 08:13:09 08:36:03 15175' 2800'
BEE13Y 10/06/2010 08:06:55 08:45:06 15000' 1500'
BEE13Y 11/06/2010 08:06:27 08:32:35 15250' 2925'
BEE13Y 12/06/2010 08:17:30 08:33:46 15000' 2875'
BEE13Y 13/06/2010 08:20:48 08:40:59 17450' 3000'
BEE13Y 14/06/2010 08:22:26 08:48:11 15000' 1525'
BEE13Y 15/06/2010 08:09:55 08:40:52 15000' 1125'
BEE13Y 16/06/2010 08:13:34 08:34:55 15000' 1150'
BEE13Y 17/06/2010 08:10:38 08:33:39 15000' 1250'
BEE13Y 18/06/2010 08:06:42 08:42:58 15000' 1250'
BEE13Y 19/06/2010 08:05:56 08:34:51 15850' 1375'
BEE13Y 20/06/2010 08:33:26 08:53:15 18975' 1225'
BEE13Y 21/06/2010 08:09:15 08:33:30 15000' 2600'
BEE13Y 22/06/2010 08:16:47 08:34:42 15000' 2575'
BEE13Y 23/06/2010 08:14:04 08:34:53 17225' 2850'
BEE13Y 24/06/2010 08:16:52 08:48:29 18050' 2900'
BEE13Y 25/06/2010 08:06:54 08:26:22 17225' 3275'
BEE13Y 26/06/2010 08:15:48 08:43:36 17825' 1325'
BEE13Y 27/06/2010 08:24:11 08:43:30 15275' 1700'
BEE13Y 28/06/2010 08:14:59 08:32:19 15000' 2625'
BEE13Y 29/06/2010 08:08:07 08:34:17 17475' 2775'
In all cases, the subsequent flight was BEE6CM, so those are at least two flights that always arrive and depart, respectively, from the same airport (which I'm pretty sure is Gatwick in this case).