Recommend minicab company from Heathrow?

Hello! I will be heading to Southampton for work at the end of the month and my flight arrives at Heathrow. Now I need to figure out a way to get to Soton from there.

I've been searching online for reviews on minicab companies to book my hotel transfer but it's rather confusing with so many companies and conflicting reviews around. Has anyone used any of the pre-booked minicab services before, and recommend a company?

I can spend up to 120 GBP if that helps.

Thanks :)