I stayed in the apartment in Valetta from the 3rd to the 10th of May and had a very enjoyable and interesting time.
The key-handover worked perfectly, even though I arrived rather late (11pm). Mark (the owner) was also very nice and helpful and made sure my stay was pleasant. The apartment was located close to everything necessary and it was very nice and clean. The only thing worth mentioning to those considering taking this apartment is that the marketplace (at which it is located) is a daily one, however if you close the blinds, you will not be woken up in the morning by the noises of setting up.

I definitely recommend Mark and his apartment!