I used the 19:39 Southeastern trains service out of Victoria for Dartford after eating at Browns at Victoria with a class 465. The journey to Dartford I believe is just over an hour and I got off at Kidbrooke next to my Aunty's house which is normal if I decide against Lewisham because I confident I can connect with a 178 bus a few stops to Kidbrooke Park Road/Eltham Road. I went to use the toilet onboard 465196 and the door was locked for the 30 minutes of travelling to Kidbrooke. I did see a key hole and I am wondering if staff would lock a toilet for the duration of a journey, I come to London to see my Aunty 13 times a year and I normally use Southeatern trains but it was unusual as I am pretty sure nobody entered the toilet, any thoughts ?