not sure to be honest mate, you can always return the tickets for a refund if the dates move, at least it looks like you can do:
4.2 Refunds of Home Match Tickets will only be granted if the Home Match Ticket is returned to the Club's Ticket Office no later than 14 days before the commencement of the Match. Where a Match is cancelled, abandoned or postponed and subsequently rearranged a refund of Home Match Tickets will only be granted if the Home Match Ticket is returned to the Ticket Office no later than 14 days before the date of the original Match or by such later date as the Club may publish on its Website as applicable. A refund will only be issued on production of identification that the individual requesting the refund is the person to whom the Home Match Ticket was originally sold. For the avoidance of doubt in the event of any dispute, the final decision belongs to the Ticket Office Manager.