Dr Lota's finding that registrars discharge patient less often from outpatient clinics fits in with common sense and the observations of most GP's. Assuming that the pattern he finds is a general one across the nhs - savings could be made by reducing the numbers of patients seen by registrars in outpatient clinics, assuming the patients are not seen instead by specialist nurses - who virtually never discharge patients!
However, surely it is the PCT's that bear the cost, not the trust. The £108 tariff represents income to the trust, and if the registrar is free then this becomes a surplus. Trust managers are not stupid, so this situation is likely to continue as long as the internal market continues.
It is also worth remembering that as well as costs to the taxpayer, the patient may have to take time off work, and that visits to distant outpatient clinics generates carbon emissions.

Competing interests: I am a taxpayer