Openreach charge is £99 per month. Not sure what the extra £41 for the BT Wholesale price covers.
EDIT : And the question was answered by IgnitionNet... So, £41 for the backhaul etc. If not done via BT Wholesale then the ISP would presumably need to put their own equipment in the exchange and pay for running that equipment and interconnects.
Edited by ian72 (Mon 04-Sep-17 15:58:34)