Apologies if this is a really silly question...what are the typcial servicing intervals on classic morgans?

I test drove a +4 a few weeks back and the dealer said it had to be serviced every 3,000 miles. If I buy a Morgan, it will do up to around 20,000 miles/year so servicing every 3,000 miles would be a major hassle. Is the servicing interval he quoted me really the case??