Marvellous open diamond frame

This bicycle in the Velorama museum is really a  mystery. It has serial number 85350, which gives at least the impression it was built by a large factory. It looks a bit like some CMC models, the frame is clearly inspired by Rover: but it isn't a CMC or Rover.

The bicycle is loaded with interesting details, like the chain tensioners and  the massive bolt on top of the seat stay. It should be recognisable....

The clue we have, is tht eaxactly the same cycle is shown in a picture in the antique  Dutch book 'Een halve eeuw Wielersport' by George Hogenkamp. This shows a picture of  a proud sportsman, named W.G. del Baere, who set some speed records on hard tired safeties, for instance in 1891. The book doesn't say if this bicycle was used in 1891, I would guess it was some years older.

So, who knows  more about this one? If you do, please, send me an e-mail.