We stayed there for a week with 2 kids (aged 2 and 5). We enjoyed it a lot! The landlord is very nice and family friendly. We even could have gotten a high chair for our little one.
The flat is beautiful. It was clean and well equipped. It also offers a nice view over Rickmansworth. Moreover, its location is really perfect: Tube station, Supermarket, Pharmacy, and High Street with more shops are all within 5 mins walking distance, which is super convenient, in particular if you also arrive by train as we did.
We can truly recommend this accomodation and there is maybe only one thing which we think could be improved: The dishwasher is installed wrongly (the front panel is too long) such that the door cannot be fully opened and the lower drawer cannot be properly pulled out. This is annoying, but then again it's just a small issue that could be easily fixed.