Hi, yep I know what you mean about the "dreaded, sharp inhale of breath through clenched teeth, you know what."
As a type one you are indeed VAT excerpt on the likes of sensors. (There should be an option to declare being exempt?)
Up until very recently regarding purchases of the Libre, I signed a VAT exemption form kept on file at the chemist I purchased them from. Any pharmacist I haven't delt with before would ask & I would tell them I'm already on file. Job done.