Hello,
Openreachpeep, you are quite right (well, you should be, you do work for Openreach after all

), Openreach raise their own charges to the service providers, and then it's up to BT (or your service provider of choice) to pass the charge on to the customer or not. Openreach engineers will not know whether the service provider will raise the charge to the customer.
The BT connection charge is only raised on very specific occasions, e.g. where there is no suitable BT line available in the property or no dialling tone on the line, and the BT advisor that is placing the order will let the customer know of the charge (if applicable) before they complete the order.
All the best,
Stephanie
BT Support