Or just take it to the place where you had your MoT done and get them to sign off the VDR, take it back within 7 days and make sure you get photos, receipt for VDR check, receipt for producing it at cop shop - then if they pull you again for the same thing you have concrete evidence that they are:

(a) wasting police time
(b) harassing you
(c) all just tossers

Wouldn't suggest trying the third one in court though