I have only managed to trace my Swallows to 1670 with some still to be confirmed.
My line is:
Ellen Louisa Ann Swallow born Harpenden Herts Feb 1881
Enoch Swallow born Harpenden Herts Dec 1842
Thomas Swallow (Swaller) born Harpenden Herts May 1812
George Swallow born Kimpton Herts 1772
John (Jno) Swallow born Wheathampsted Herts 1728
John (Jno) Swallow born Kimpton Herts 1698
John Swallow born ? 1670
It is quite possible as these area are not too far from Welwyn that there could be a connection.
I am not sure if I will ever establish a connection to the 1st Lord!