Greg Lansdowne informs me that card no. 310 is supposed to be Steve Castle of Leyton Orient, but the photo on the front is actually Terry Howard. They did however, get the correct photo on the back of the card. Unlike many error cards in this collection, this one seems to have gone uncorrected.
The full checklist can be found here - Pro-Set - Footballers (1990-91).
310. Steve Castle (Leyton Orient) - photo of Terry Howard