We have had hammer tap bothering us and the upper maisonette above us for several months. next door have the same problem. Thames Water not interested in this coincidence and are claiming that even if their pressure has increased, thus probably causing the hammer tap to 4 maisonettes, they won't help us fix it.
We've bought our own hammer tap arrestor and fitted it today - it seems to be leaking a little though (about 2 drops/minute) and our plumber's coming to have a look soon.
But what really worries us is that in spite of being now connected in our toilet cistern, the hammer tap is still very much present.
Where have we gone wrong?