The flat was perfect. Very clean and especially quiet - located directly on the edge of Holyrood Park - so we could even sleep with the windows open. It was an easy 20 - 25 minutes walk towards the old town city center. The only little draw back was the musty smell in the en-suite bathroom (not sure if it was caused by the drain in the shower or the carpet in that room), which would even linger when we had the window constantly open.
But overall, absolutely recommendable. Thanks Gill also for the very nice welcome (including coffee and snacks).