Just had a look in a mk1 service leaflet....
Petrol
A Service - 10,000 miles or every year,whichever is sooner.
B Service - 20,000 miles or every two years, whichever is sooner.
Major Service - 40,000 miles or every four years, whicever is sooner
Diesel
A Service - 6,000 miles or every year, whichever is sooner.
B Service - 18,000 miles or every year, whichever is sooner
Major Service - 36,000 miles or every year, whichever is sooner.
Thats the intervals but i cant be fucked to right up whats been done, should be a handbook with one of your cars surely.