The Spectrum branded boxes are made by Humax, Technicolor, or Arris depending on the model number. Try the codes for one of these.
Ex: Spectrum 101-H is made by Humax; 210-A made by Arris.
Im looking for the Spectrum 110-A not the 101-H
The 110-A is made by Arris. Try codes for Arris.
Since these boxes are made by various manufactuers to the same standard, if an Arris code doesn't work perhaps a Humax or Technicolor code will.