Given that BNFL (or whatever their name is today) have both removed the bus subsidy and are making it increasingly difficult to drive on-site, this can only be a good thing - as long it stays.
I am unsure of the current situation but it was the case that you were only allowed to drive on-site if you had 2 or more people in the car (to encourage use of the buses... which now aren't there).
They are going to be moving a large number of people to new offices based in Whitehaven within a few years, this is good, if people do not need to be on-site they shouldn't be, bringing those people into town will shorten commutes (both by distance and by virtue of people going in more directions, ie quicker) and bring business into the town (people out for lunch etc).
There will always be people required on site and the more that can go by affordable and timely public transport the better.