Yeah, the guy I just spoke to made me aware that the discount will be £44.94 as opposed to £37.94 to cover the extra £7 but said they don't/won't refund the £3.50 as it's a partial month's charge.
I did, however, managed to get the £35 installation charge credited to my account before the DD goes out from the bank in a few days, but forgot to ask about the VHD box upgrade. D'oh!
I also managed to get an engineer booked for tomorrow AM to check the increasingly flaky SA V+ box.