Hi Nigel,
Sorry, I should have tried to explain that quote, "Until 1823 only, there was also the obligation to enter a bond, although these were rarely forfeited". It refers to a change in Church marriage law which came into effect in 1823. The Hardwicke Marriage Act of 1753, made it illegal for those under the age of 21 to get married without the consent of their parents or guardians. Prior to this, the age at which one could marry without parental consent had been 14 for boys and 12 for girls. The Hardwicke Act made parental consent necessary for many more people and so "the obligation to enter a bond"which existed only until 1823.
It is a bit misleading as I believe that under-age people could also marry by banns. They were not obliged to obtain a licence. With the new law of 1823 the ages for marriage without consent reverted to 14 and 12. This really had little effect on the number of people choosing marriage by licence as it had become the fashionable thing to do, if you could afford it.
Hope I explained this well enough to clear up the puzzle.
Cheers,
Carmela