Last night was opening night at the club and we welcomed a number of new potential members. There was some discussion about printing and how best to mount prints. Here is the supplier we generally use for slip mounts for monthly competitions. There is a minimum order of £20 before VAT and carriage costs. The club usually orders several batches in a season as required but if you prefer to order your own the usual size for the mount is 14 x 11" for A4 prints.
http://www.cotswoldmounts.co.uk/products/slip-mounts/white-core-slip-mounts