I do a lot of digging on Google to make sure that all the company names I use are fictitious. I also tend to look up people in a particular field, to make sure I'm not naming a rogue after them.
All that said, it's impossible to use names that are unique, especially when writing about the present day UK. It is worth repeating that;
All characters appearing in this work are fictitious. Any resemblance to real persons, living or dead, is purely coincidental.