Did the last remaining building of the Redditch factory really belong to Royal Enfield?

The Redditch factory in Hewell Road was demolished a few years ago to make way for the Royal Enfield Business park. There is one remaining building from the time,

They have placed a stylized sculpture of a bike in front of it and has the little round plaque that the Royal Enfield Owners Club had placed commemorating the factory (it was originally placed on another building that was demolished). They also painted the Royal Enfield logo on the side of the building,

It belongs to Prestantia Eco, which lists its address as "Enfield House, Royal Enfield Business Park, Hewell Road, Redditch". Rather tastefully, they kept their modern signage at the back of the building,

I always found that building rather odd, it was at a 90 degree angle with respect to the other buildings of the factory, and had a different construction style than them,

In Anne Bradford's book there is a map listing the various buildings. It is hand drawn, rather schematic, and not to scale, so it is not easy to identify the individual buildings in the picture.  But a building roughly in the location of the one we are discussing says it did not belong to the factory but to Terry Springs (which owned several other buildings in town, having being founded in 1855 and still going strong) and that Major Mountford, the Enfield CEO in the 1950's attempted to buy it but failed. 

It would be good if this could be corroborated. Any readers out there with knowledge of this?