Surrey Tuning say they use RacingLine software on their website, which is normally expensive, like all of the other overpriced rebranded stuff RL sell, so £290 isn't a bad price.
The remaps on offer from various companies are all much of a muchness. I've tried a few different ones and couldn't discern a massive difference unless you specify something a lot wilder than the norm, so personally I would just pick the company closest to you, which preferably also has decent customer support in case of post-sales problems.