DEC LGW is the onto the usual, perm, union agreed LGW contract just like any other skipper based there.
No flexi, no random roster, no base freeze as far as I know. You should be on 5453 from day 1. Other bases are a different story.
Hours depend on base. LGW is hard work. I'm in a regional and fly about 750 a year and feel quite OK most of the time.
Some long days for sure but also some lovely 2 sector trips where I am.