Originally Posted by Ratmagiclady
Gaffer tape?
(Or: have you asked Pentax? They might send you one. Easy way to leave a positive impression. )
My thinking as well

. Got in touch with them and this is what they sayeth
Thank you for contacting Pentax.
Pentax does not sell the cap separately. I'm afraid you would have to purchase the hood to get the replacement cap.

Pentax, no country for lost caps.
Tape it shall be