It's quite possible that what I described as lemon was in fact bergamot, P&B, or possibly even grapefruit. Once it is preserved in a heavy syrup I find it difficult to distinguish. I just remembered that I have also had rose syrup. I think that typically the taverna owner will have made it themselves from whatever they happen to have rather than buy the fruit. Around my area the main crop is citrus fruit so they are likely to own citrus trees. In northern Greece citrus trees don't do well, because the temperature drops too low in winter, but quince is widely grown. Hence the variation.