R.N Speirs had a big presence in Foxton and MAVtech has a range of cinema advertising slides showing them advertising timber and cooking appliances! This particular slide is advertising an infra-red electric heater.
Foxton has plenty of late 19th/early 20th century villas and Foxton Beach is famous for it's batches. Both have plenty of character and charm but not a lot of insulation! A heater would be just the thing during a cold, wintery day. This slide would date from the 1960s (approximately).