Typical stressful agency. Pay is ok.
They will take on any crap project as long as it pays in pounds. That's the entire business model. Set up shop in Cape Town, pretend to be a London business, bill in British Pounds, and pay salaries in South African Rands.
Because most of the work is from other agencies they have very little say in timelines, so the project management is very poor. I'd stay away unless you have no choice and just need some experience. Then I'd jump as soon as you've got it.