What happened to the 'REAL' Mars Bar?

I think for our US friends it might be worth mentioning the UK Mars Bar/Milky Way, isn't the same as the US versions. I think it was around 2002, Mars re-arranged the ingredients for a newer variation of it.  Then there's also the close family connection with Snickers bars, named after a race horse owned by the Mars family.

The Mars factory on the Slough Trading Estate was formerly owned by the government. It used to be a repair depot for military vehicles which I think, was one reason there was a branch line into the Estate off the Great Western Railway passing by, plus for supplying fuel for its own power station.