The flat is exactly as described and was really clean and airy. Beds were really comfortable, which is always important, and you have an en-suite and family bathroom. You have everything you need for the stay, and we had cereal, bread, milk etc left for our breakfast.
It is about a 15 min walk into Malahide, which was buzzing on a Saturday night and had enough bars and restaurants for daytime and evenings.
Dublin is 25-30 mins on the DART from the centre of Malahide and trains run really regularly. We tried the bus, but it was hot and really busy, so we preferred the trains and the cost was about the same, and you don't need the right change like you do on the bus.