At what time of year are the most in births in England and Wales?

An article Do humans have mating seasons? This heat map reveals the surprising link between birthdays and seasons caught my attention.
It showed a consistent pattern across high-latitude countries in the Northern hemisphere -- the months with the greatest average number of births per day were July, August and September.
But that wasn't my recollection for England and Wales statistics, so I went back to FreeBMD.
There birth registrations peak in the second quarter, not the third for the period 1838 to 1979.
There's not necessarily a conflict, the article references 21st century data sourced from the UN.
To examine if there was a trend the FreeBMD period was divided into four, 1838 to 1849, 1850 to 1899, 1900 to
1949 and 1950 to 1979.
For none of these was the peak in the 3rd quarter. Each quarter in the first half of the year had more birth registrations than the 3rd, with one marginal exception.