In the H&S mad world we now inhabit , you find that you very much have to play by their rules as fanatic says the most you get is glorified taxi . I had a spell as a first responder , had to give it up with change in occupation, but was ready to pull the pin anyway. You are not there to give a rapid response service, but to enable them to tick a box. We even had the situation where they bought two cars had them all battenburged, and fitted with blues etc , marked in big letters Ambulance First reponder. Then said if we wanted to be able to drive them had to have driving assessment, which I did , flying colours pass, ( I should think so with previous police and fire brigade training and more than 25 years such experience) . There was a key down by handbrake , so asked whats that for? "so we can lock off blues& twos when you use it " I kid you not . They didn't want you to up your skills , as they just want you to do what they needed out of you at your own expense , and time .
On the insurance thing , if its voluntary not using blues, your ins co will quite often include the cover for no or very little extra (NFU did for me)