Pros
Knowledge sharing was part of the culture so the place is great to learn from others. While it gets harder as the company grows most of the systems are designed well and in line with best practices / company standards. The level of access granted is the almost whatever you can prove you have the knowledge/skills to work with. Great social and friendly teams although the very top brass rarely joined for more than one drink. Office in Bank has great transport links and local food vendors. Allow for sideways training into other departments e.g Engineers to Project Managers, Service Desk Managers. Good Bonus based off performance. High standards for change request/ticket notes make them perfect resources for learning. Usually use the best technologies for the task instead of the cheapest.
Cons
High amount of dedication required. Salaries are generally below the market average for London. Harder for people to fit in if they cannot attend socials / dislike visits to the pub after work. Internal promotions are common but has a lot of competition and there is a small amount of politics in some of them. Lack of knowledge database. Lots of management changes recently Lacks benefits.