Just got back from Arillas, I went with 28kg of clothes etc in my suitcase. Didn't get charged , although I was over by 8kg (at Gatwick).
But the maximum for 1 case is now 32kg because of health and safety issues for the baggage handlers, to mind their backs! so if you are going as a couple best not to go over the limit by putting it all in the one case.
Had a great time there, would recommend it, did not like Sidari or Corfu town............too busyand full of tacky shops.
Best shop for my nephews was Ina's on the front, the thought it was an Aladdin cave and staff were lovely to them.