I've done this kind of thing before and I can assure you that even if no money changes hands this is legally a private hire and therefore is required to run to EU Driving rules in order to carry passengers. It's a grey area but the company offering a vehicle free of charge for employees is deemed to be an employee benefit and hence 'a reward'.
I think there are two slightly separate issues here. To take the second point first, an employee benefit or reward (normally used in reference to when tax might be due) is a benefit or reward which accrues to the employee. And yes, a free private hire, is indeed a benefit/reward to the employee ( I’m no tax expert so won’t go into the theoretical taxation debate). The legislation around carrying passengers for. ‘Hire and Reward’ however, means a hire by a company for which IT gets a reward (ie payment). A bus company providing a free vehicle for a hire is not getting a reward out of it, so it’s not strictly hire and reward. Therefore (similar to a preserved bus), whilst the driver needs a PCV Licence if there are more than 8 passengers, the bus doesn’t need to be a PSV or display an O Licence. Now of course, bus operators run PCVs on O Licences, so in reality the bus/coach used on the free hire will run with an O Licence. The driving rules question is more interesting. Most companies if using a tacho fitted vehicle would use the tacho and ensure the driver complied with EU hours to avoid any potential arguments with DVSA. However, whether this is legally required is less clear. Certainly if a bus was used, which was not tacho fitted, there would be a strong argument that was perfectly legal proving no payment was changing hands.
