I've just rummaged around in my tub of potatoes & found quite a few fairly big ones, but they are scabby, having never grown any before i have no idea what I have done wrong. They tasted good though!
Although scab don't look good it does not spoil the flesh and whole potatoe is perfectly edible..as you have noticed.. ;D
some varieties are more prone to it than others..and presence of lime in soil will encourege the scab...that's why potatoes like soil that is more towards acid than alkaline..
Also if the soil in tubs have been irregularly watered it does encourage the scab...regurlar watering..and constant moisture and resistant varieties is the answer if you want spotless spuds.. ::)..yeah I know...easier said than done..
At least you enjoyed them..scabs or not..that's the main thing.. ;D
It's the taste that counts & the fact that I did it all by myself - must admit watering was a bit hit or miss & they got severely frosted.