We have saved around 1000 pounds per month since DD2 was born, at the advice of a financial adviser who thought we could manage this (it was about 1/3 of our monthly income, with the mortgage being in the region of 1000 as well). The reality was that we signed up to it, then found that we couldn't easily manage, but could if we shopped at Lidl/the market and had no luxuries. I absolutely loathed this and hated the financial adviser for several years.
However, I then got a promotion at work, which meant a significant increase to my salary. This made life a bit easier, in that we could have some luxuries, but I was spending around 450 on commuting every month, which rather ate into the increase, but still meant that we were a bit better off.
Fast forward a few more years, and we moved to Paris, which meant another increase in salary. So we are now reasonably comfortable and have a significant amount of savings, which we can now access (it was tied up for 10 years minimum). We are choosing not to pay off our mortgage, but are overpaying on it, due to low interest rates. The money will probably be used for school fees, if necessary, or university for the DDs.