I think waiting for another test to see what the trend is, is sensible - the fact that it has been 0.2 for two tests doesn't really give a picture of what is happening. But Ali, I think unless the PSA has gone back down at the next test you should ask to see the onco regardless. Peter shouldn't have been discharged from oncology even if monitoring was passed back to the GP so it isn't a case of needing the GP to re-refer.
Whether it was a G6 or a G9 doesn't make much difference right now - if it has recurred, it has recurred. If the PSA rises at next test, the interesting discussion with the onco will be about what scan tracers are available in your area and when is the best time to do the scan.