I seem to remember that JCB the excavator company managed it with an HS125 once (mid 80's?)
I think they traded up from a -600 to a -700 and the reg stayed the same. G-OJCB or something like that.
edit
Just checked the CAA database and it was G-TJCB a -700 exported to Denmark in 85, there is no mention of the other 125, however I really do remember something in Aviation news, it even has a picture of the two aircraft I think.