Only thing to do is to fence in the area that you want to protect. The wire will need to be buried to a depth of several inches/a foot to stop the rabbits burying beneath it. Buy a good, wide roll of wire mesh and bend the bottom of it out into the form of a capital 'L' and bury this in a trench. The rabbits will hop up to the fence and then try to bury beneath it but find that the bottom of the 'L' prevents them from doing so.

There's no easy answer. Nothing will stop rabbits short of a complete fence with the bottom six inches or so buried in the earth and curved round so they can't dig through. You might try keeping a dog chained up in the garden at the points where the damage is being done, as that should deter them, but the dog may not be too happy with the idea!
Personally, I would use a humane trap (the sort with an entrance that falls down catching the rabbit) and then dispatch them humanely. If they are healthy this would be a good source of meat to liven up your vegetables, and with perseverance you could reduce the numbers substantially.

A few yeares ago I developed problems with rabbits coming onto my small nursery for a snack. My nursery is covered with tough ground cover sheeting and I put a chicken wire fence around it and just pinned the wire to the ground cover .The rabbits can't dig through the ground cover so can't get under the fence.

Dried chilli flaves stopped them uprooting the plants out of my pots and troughs, a few of us have tried it with some success, need to keep doing it especially after rain which is why flakes are better than powder.......i,d wash the lettuce well before you eat it......