According to the Practical Law website, different rules apply to copyright arising before the Copyright, Designs and Patents Act 1988 came into force. Transitional provisions in the Act mean that many unpublished artistic works continue to enjoy copyright until August 2039 even though their creators died many years ago. It goes on to say, "The complexity of copyright law governing images created before 1989 means that where there is any doubt, it is safest to err on the side of caution and assume that a picture is in copyright."

In any event, when the images were bequeathed to VWML this was presumably immediately after Sharp's death.