White Cliffs of Dover

I didn't know there were jungles in Kent! Much less that there are jungle tours there.

Honestly, that's a new one on me.

Seven Sisters allows you to get up close and personal, but is down the coast.

You could take a day trip to Calais and see them as you leave and return.

I've never heard of a boat trip to see the White Cliffs. The whole point about the cliffs is you can only see them properly from the sea, they are the last thing you see of England when you are leaving by ferry and the first thing you see when you return (or they were until they built the tunnel).
Maybe this is a business opportunity for someone in Dover.

I too would recommend the Seven Sisters. These are a similar set of cliffs further along the coast, but, due to the shape of the coast, you can see them from land.

The same white cliffs are on the French side.