Servicing

I've just had my car back from it's 4th service. As I only do about 5,000 miles a year (usually just use the car at weekends as I take the bus to work each day). I thought I was on fixed servicing interval but the log book has been marked up as if the next service is to be a variable service. The invoice shows 40,000 mile service but makes no reference to spark plugs having been changed/charged.

The parts section of the invoice shows longlife oil and filters presumably air/pollen.

Is the service I have received correct?

Thanks