Spanish Customs
The terms 'Spanish practices' or 'old Spanish customs' are British expressions to describe malpractices, originally referring to irregular or restrictive practices in workers' interests. Typically, these are arrangements that have been negotiated in the past between employers and unions.
Why it matters
This is a pejorative term, especially to people of Spanish origins.
Instead try saying:
Unofficially agreed ways of working
Undocumented Agreement/Process
Further External Reading Link