My first job in "civvy street paid £7 per week.This would be above a tradesman's wage. I would describe it as lower management. An ex R.A.F friend who before entry into the R.A.F was employed by Priestman Excavators Ltd, was re-emloyed as a representative at the same wage. £80 would equate to eleven weeks wages . Which would be near or similar to your calcuations.