The bank of England issued national government bonds from 1693. These were modeled on bonds issued earlier by cities and Provinces in the Netherlands.

So, yes, there were government bonds in the 18th century and the wealthier sections of the populace were generally the people who bought them.

British consuls were particularly popular. These were a form of perpetual bond (bonds which never expired - the capital was never repaid - the interest went on forever - though the British government had the right to call them and repay the capital any time after (usually) five years. These bonds were first issued in 1752 at 3.5% interest. By 1757 the interest was reduced to 3%. It remained there until 1888.

3% Interest in an era of essentially 0 inflation, from a source perceived as risk free, was an attractive and popular investment.