You can replace the air filter and cabin filter yourself. It's very easy to do, it's not a dirty job and you can buy them anywhere. They don't have to be Mazda items. I paid about ?25 for the two filters for my car.
I'm sure any garage can do the engine oil and filter change for less than ?200.
Is the calibration really necessary after 33,500 miles? If the car is running OK and fuel consumption is OK, calibration may not be necessary. Perhaps someone else can throw some more light on this item. My car is petrol so not needed.