They need to curb the reproduction rates of a certain group of people in the UK known to be 10 times that of indigenous British people.

If people are so unhappy at being parents, it is no surprise if they are constantly brow beaten by anti family writers like yourself.
As a liberal intellectual you no doubt find your greatest joy in robbing people of meaning in their lives. Is this because you are bitter yourself? Do you care how many people you might tip over the edge into depression? Does it make you feel better?
Personally I and my wife live for our kids. There is nothing greater nor more significant than founding a family. Every joy comes from the children. The ramifications in creating a family are that you are actually creating thousands of new wonderful people in your own image, far into the future.
The greatest peace of mind is in knowing you have followed the eternal laws of nature. That you are a winner just like all your millions of ancestors.
There is joy knowing the golden thread continues and a smugness that the childless are natures' losers on the road to genetic extinction.