In theory you can go get in any glider & fly solo without a single lesson, though trying that at any UK club would get interesting response
Are gliders easier to fly than power? - that's like asking if a Evans VP1 is easy compared to a 747, depends what you are flying & what your doing. Flying a competition with 30+ gliders constantly fighting for the lead in a modern high performance single seater has a huge workload over a considerable time & is not for the faint hearted, pottering around on a summers day or doing some aerobatics is pure enjoyment & should not to be missed by anyone.