Bought tickets today for this game and was told the same about lower tier only. Was curious how many this held and found the below.
Away Fans
Approximately 4,000 visiting supporters can be catered for and they’re housed in the Darwen End of the ground. How much of this stand is allocated to visitors depends on the likely size of the following. Where the demand is less than around 2000 seats, the lower tier to the right of the goal (as viewed from the pitch) is normally used. If more away supporters are expected, the upper tier is used and, for the biggest followings (and sometimes on security advice), the whole of the stand will be given over to visiting supporters. The views from anywhere in the stand are very good.