I lived in or around the Spelthorne for many years.
Spelthorne BC was only created in 1965.
Spelthorne as a parliamentary seat goes back to 1918 and all of the towns / villages would have been in the County of Middlesex.
The parliamentary boundaries in 1918-1945 where the Urban Districts of Feltham, Hampton, Hampton Wick, Staines, Sunbury-on-Thames, and Teddington, and the Rural District of Staines.
As I cannot find any reference to Teddington Lower Ward, can you let me have a link to the source and I'll see what I can work out.
Edward