Pros
A good place to start as a graduate since you learn a lot about industry and working in a critical application. Also, as a graduate you get raise every 6 months so after two years you will earn more than £40k. The place is really easy going and as long as you do the required work, no one cares how much time you spend on a break etc. Bonus around 8%-10% 28 days of holiday per year
Cons
Location is really bad. It's located near Heathrow Airport so nothing around besides a pub, really noisy outside the building and it will take a lot of time commuting to get there even from west London. There is not much room for development. You may be lucky and work in a new project but most probably you will be 90% maintenance - 10% development. After two years when you finish graduate scheme and are promoted as Software Engineer, you will take yearly raise in the region of 3.5%. No training is provided. They expect you to figure out everything yourself. Code is really messy, we are talking about methods having thousands of lines of code.