Pros:
The house is in a great location on a short pedestrianised road, only a few minutes walk from the centre of Valletta. (Taxi from the airport was unable to find it and I had to resort to using Google maps on my phone. Best to be prepared for this.)
The house has lots of character, definitely not a boring modern cookie cutter clone.
The bed was extremely comfortable, much more so than it looks in the pictures.
Communication from Zoe was very good throughout our stay, responding to messages within a few minutes.
Cons:
House has a damp problem. The provided dehumidifier needs to be run constantly and emptied 3 or 4 times a day.
When we arrived the water heater for the kitchen had developed a leak and flooded the downstairs. Zoe got a plumber out very quickly, who unfortunately had to disconnect the water heater. It took a few days to get parts, meaning we had no hot water in the kitchen for the first 4 days. I had assumed that this was also impacting the shower upstairs, but we eventually realised that upstairs has very low hot water pressure. Showers can be strong or hot but not both. I suspect that this would be much less of an issue in summer.
One night (after the water heater was repaired and working) I switched off the fan heater and saw a flash from the socket and blew the main fuse for the house. As it was late at night, we decided to just drop a message to Zoe so that it could be resolved the next day. Zoe's husband was around first thing in the morning to try to resolve. He got an electrician around that morning to replace the fuse.
Overall:
As I say, we were a bit unlucky with some of the issues during our stay, but with the probable exception of the damp, I think these were isolated incidents and unlikely to be a problem for anybody else staying here. Zoe and her husband were always quick to respond to any issues and gave us an unprompted partial refund as a goodwill gesture because of the issue we had.