How much ‘discount’ were you expecting if you stop using BT for telephony completely ( so no phone number associated with the broadband, no incoming calls as well as no outgoing, including no 999 calls etc ) because you refuse to use the SH2 thereby being unable to make use of it ?,
The official list price difference between BT Broadband with telephone and the identical BB package without the telephony is £5 a month , but quite often the telephony price is discounted , if you were a potential new customer willing to pay list price for BB and phone and reconsidered and asked for the phone service element to be removed , the phone service cost of £5/month is what you would save , if an existing customer has had the telephony cost discounted , then obviously the saving is cost the discounted telephony , not £5.
if BT supply you with the means of using DV ( a router that is designed to deliver DV and a suitable handset or adapter ) but you chose not to use the supplied kit , then it’s yourself rather than BT that are making telephony inaccessible, but they do offer broadband only that is slightly cheaper than BB and phone , if you take that option , you would then have to make your own arrangements for telephony
