If you did not want to sit in the red area then you could either call the call centre (it is quite unlikely that all of he West stand will be sold out) or you get told the seat and row number when you are buying the ticket and you can press 'cancel order' and go buy a ticket in 'West stand lower' again. I sat in the red area that you showed us in the picture and I was in Row 13 seat 200. There are 32 rows in the west lower so if you want a good view of the whole pitch try to get a row with a number higher than 20 and the seats that are not in the red area have a seat number of less than 200. For example, f you get offered Row 24 Seat 114 that would be a very good seat for you