Only couple of years later...
David Prowse was fully concealed in another role where he gets his marching orders from Peter Cushing...
"Enough of this. Vader, release him."
... and a few more years later, Shane Briant returns as Simon Helder in "Sherlock Holmes vs Frankenstein" :)
https://www.facebook.com/holmes.frankenstein/
You just can't kill Hammer's legacy.