I don't know about treatment of the elderly in NHS hospitals although I have heard it can be bad. What needs looking at is when you have to come off warfarin to have a test or operation (bridging therapy).
My brother, who has an artificial heart valve, had to go in earlier this year and they completely messed it up so that he was left with no "cover" his INR was 0.6 for three days until I said that if they did not put him back on heparin he would probably have a stroke. That worked!
Doctors and nurses need more education training about warfarin and bridging therapy.