I found this guy in Sotherby's program for the London sale of 1995, 'Talk of Buddha' was starting at £3000, not sure how much it sold for or if it did. Online it seems to suggest it is still the property of Ernest Cooper of whom it belonged to before the sale too. Roberts' style i find is very much akin to Fernand Leger on his more tubist pieces. They were both contemporaries though Leger may have hit the scene a little before Roberts.
Talk About Buddha
The Rhine Boat